diff --git a/README.md b/README.md
index 6a8db16d7..6fef6111c 100644
--- a/README.md
+++ b/README.md
@@ -1097,6 +1097,22 @@ under `web_fetch` or use `TAVILY_API_KEY` for both.
 
 ### Private Knowledge Retrieval (RAGFlow)
 
+Answers can cite retrieved RAGFlow evidence with clickable knowledge citations.
+Click a citation, or an entry in the answer's knowledge sources list, to see the
+original retrieved excerpt, dataset and document names, and page numbers when
+RAGFlow supplies them. These are retrieval-time snapshots retained with the
+conversation, including sources forwarded by ordinary `task` subagents; they
+remain inspectable after reloading the conversation. An excerpt is not a live
+copy of the full document: changes in RAGFlow do not rewrite past evidence.
+Missing source records are shown as unavailable rather than turned into guessed
+links. Source snapshots do not add a knowledge-management page or expose the
+RAGFlow API key. Durable batch exports and standalone Markdown files do not
+carry these interactive conversation source records.
+Ordinary document-title links in a Sources section open the same evidence as
+inline citations. When a tool-output budget applies, only complete evidence
+entries that fit remain citable; omitted sources are reported rather than
+retaining a source record for a cut-off excerpt.
+
 DeerFlow can optionally connect to a tenant-scoped RAGFlow deployment. The
 `knowledge_search` Agent tool resolves the configured dataset scope, groups
 datasets by embedding model, and retrieves those groups in parallel so mixed
diff --git a/backend/packages/harness/deerflow/agents/middlewares/tool_output_budget_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/tool_output_budget_middleware.py
index 05e44225c..54825cc81 100644
--- a/backend/packages/harness/deerflow/agents/middlewares/tool_output_budget_middleware.py
+++ b/backend/packages/harness/deerflow/agents/middlewares/tool_output_budget_middleware.py
@@ -44,6 +44,7 @@ from deerflow.agents.middlewares.tool_call_args import ToolCallOccurrence, pair_
 from deerflow.agents.middlewares.tool_output_synopsis import render_tool_output_preview
 from deerflow.agents.middlewares.tool_result_meta import TOOL_META_KEY
 from deerflow.agents.middlewares.tool_transform_meta import append_tool_transform
+from deerflow.community.ragflow.sources import budget_source_artifact
 from deerflow.config.tool_output_config import ToolOutputConfig
 from deerflow.sandbox.sandbox_provider import get_sandbox_provider
 
@@ -480,14 +481,24 @@ def _patch_tool_message(
         config=config,
         sandbox=sandbox,
     )
-    if budgeted is None:
+    update: dict[str, Any] = {}
+    trigger = _effective_trigger(tool_name, config)
+    citation_result = None
+    if tool_name in {"knowledge_search", "task"} and trigger > 0 and len(text) > trigger:
+        citation_result = budget_source_artifact(text, msg.artifact, trigger, summary=(budgeted[0] if budgeted else text) if tool_name == "task" else "")
+    if citation_result is not None:
+        replacement, update["artifact"] = citation_result
+        transform_kind = "truncated"
+    elif budgeted is not None:
+        replacement, transform_kind = budgeted
+    else:
         return msg
-    replacement, transform_kind = budgeted
-
-    update: dict[str, Any] = {"content": replacement}
+    update["content"] = replacement
     if getattr(msg, "response_metadata", None):
         update["response_metadata"] = dict(msg.response_metadata)
     new_kwargs = dict(getattr(msg, "additional_kwargs", None) or {})
+    if citation_result is not None and budgeted is not None and budgeted[1] == "externalized":
+        append_tool_transform(new_kwargs, "externalized", by="ToolOutputBudgetMiddleware")
     append_tool_transform(new_kwargs, transform_kind, by="ToolOutputBudgetMiddleware")
     update["additional_kwargs"] = new_kwargs
     return msg.model_copy(update=update)
diff --git a/backend/packages/harness/deerflow/community/ragflow/AGENTS.md b/backend/packages/harness/deerflow/community/ragflow/AGENTS.md
new file mode 100644
index 000000000..21ffac0f8
--- /dev/null
+++ b/backend/packages/harness/deerflow/community/ragflow/AGENTS.md
@@ -0,0 +1,20 @@
+# RAGFlow citation snapshots
+
+`knowledge_search_tool` returns native `content_and_artifact`: model-visible
+`[citation:N](#knowledge-<opaque-id>)` links resolve to bounded
+`artifact.knowledge_sources` version-one evidence snapshots. Provider locators
+stay in the artifact; source names and text are credential-redacted in both
+representations. IDs are unique per retrieval, never per-message ordinal IDs.
+Only actual emitted entries get source records. Retain the exact excerpt sent
+to the model and mark truncation; do not fetch a fresh chunk and present it as
+historical evidence. Direct `knowledge_search()` callers retain its string API.
+`sources.py` forwards only captured sources cited by ordinary subagent results,
+with count/text budgets. The source dialog uses stored thread messages and
+introduces no unauthenticated document proxy. Durable batch result storage and
+standalone Markdown do not include native source artifacts.
+
+Output budgeting retains complete evidence entries and their source records
+together, including delegated results and model-request history. Never shorten
+an excerpt under an existing ID. Drop entries that cannot fit, with an omission
+notice, while preserving unrelated artifact fields. This honors per-tool and
+fallback limits without exempting citation-bearing results from the budget.
diff --git a/backend/packages/harness/deerflow/community/ragflow/formatting.py b/backend/packages/harness/deerflow/community/ragflow/formatting.py
index 7a179273a..ce2bf2061 100644
--- a/backend/packages/harness/deerflow/community/ragflow/formatting.py
+++ b/backend/packages/harness/deerflow/community/ragflow/formatting.py
@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from collections.abc import Mapping
+from collections.abc import Callable, Mapping
 from typing import Any
 
 
@@ -94,3 +94,78 @@ def format_retrieval_result(
         return truncation_marker[:max_total_chars]
     prefix_length = max_total_chars - len(truncation_marker)
     return f"{formatted[:prefix_length].rstrip()}{truncation_marker}"
+
+
+def format_retrieval_sources(
+    result: Mapping[str, Any],
+    *,
+    dataset_names_by_id: Mapping[str, str],
+    max_chars_per_chunk: int = 800,
+    max_total_chars: int = 8000,
+    redact: Callable[[object], str] = str,
+) -> tuple[str, dict[str, Any] | None]:
+    """Pair model-visible citations with bounded, immutable retrieval snapshots.
+
+    Citation identifiers are independent of provider IDs and unique per call.
+    Only entries actually included in the text receive a source record; the
+    artifact retains the same excerpt the model saw, never an unbounded payload.
+    """
+    from uuid import uuid4
+
+    chunks = result.get("chunks")
+    if not isinstance(chunks, list):
+        return "No relevant content found.", None
+    call_id = uuid4().hex
+    aggregates = _document_aggregates(result.get("doc_aggs"))
+    names = {str(item["doc_id"]): str(item["doc_name"]) for item in aggregates if item.get("doc_id") and item.get("doc_name")}
+    entries: list[str] = []
+    sources: list[dict[str, Any]] = []
+    remaining = max_total_chars
+    for chunk in chunks[:100]:
+        if not isinstance(chunk, Mapping):
+            continue
+        dataset_id = chunk.get("dataset_id")
+        document_id = chunk.get("document_id")
+        chunk_id = chunk.get("id")
+        # Incomplete or out-of-scope locators must not become verified sources.
+        if not all(isinstance(value, str) and value and len(value) <= 256 for value in (dataset_id, document_id, chunk_id)):
+            continue
+        if dataset_id not in dataset_names_by_id:
+            continue
+        source_id = f"{call_id}-{len(sources) + 1}"
+        dataset_name = redact(dataset_names_by_id[dataset_id])[:512]
+        document_name = redact(str(chunk.get("document_keyword") or names.get(document_id) or "Unknown document"))[:512]
+        # Keep untrusted names outside the Markdown label to avoid link injection.
+        header = f"[citation:{len(sources) + 1}](#knowledge-{source_id}) {dataset_name} / {document_name}\n"
+        text = redact(str(chunk.get("content") or "").strip())
+        allowance = min(max_chars_per_chunk, remaining - len(header) - (2 if entries else 0))
+        if allowance < 1:
+            break
+        excerpt = _truncate(text, allowance)
+        entry = header + excerpt
+        entries.append(entry)
+        remaining -= len(entry) + (2 if len(entries) > 1 else 0)
+        positions = chunk.get("positions")
+        pages = (
+            sorted({position[0] for position in positions[:100] if isinstance(position, (list, tuple)) and position and isinstance(position[0], int) and not isinstance(position[0], bool) and 1 <= position[0] <= 1_000_000})
+            if isinstance(positions, list)
+            else []
+        )
+        sources.append(
+            {
+                "id": source_id,
+                "provider": "ragflow",
+                "dataset_id": redact(dataset_id),
+                "document_id": redact(document_id),
+                "chunk_id": redact(chunk_id),
+                "dataset_name": dataset_name,
+                "document_name": document_name,
+                "text": excerpt,
+                "truncated": len(excerpt) < len(text),
+                "pages": pages,
+            }
+        )
+    if not sources:
+        # Legacy/incomplete provider responses still yield useful readable text.
+        return redact(format_retrieval_result(result, dataset_names_by_id=dataset_names_by_id, max_chars_per_chunk=max_chars_per_chunk, max_total_chars=max_total_chars)), None
+    return "\n\n".join(entries), {"knowledge_sources": {"version": 1, "sources": sources}}
diff --git a/backend/packages/harness/deerflow/community/ragflow/sources.py b/backend/packages/harness/deerflow/community/ragflow/sources.py
new file mode 100644
index 000000000..5fa5a4cda
--- /dev/null
+++ b/backend/packages/harness/deerflow/community/ragflow/sources.py
@@ -0,0 +1,101 @@
+"""Bounded source-artifact forwarding across ordinary subagent results."""
+
+import re
+from collections.abc import Mapping
+from typing import Any
+
+
+def budget_source_artifact(content: str, artifact: object, max_chars: int, *, summary: str = "") -> tuple[str, dict[str, Any] | None] | None:
+    """Keep whole evidence records and their links together within a tool budget.
+
+    Never shorten an excerpt under its existing source ID: those IDs also occur
+    in persisted child messages. Oversized records are omitted atomically, and
+    unrelated artifact fields survive. A task result can retain a short synopsis
+    before the evidence; its old knowledge links are replaced by retained ones.
+    """
+    if not isinstance(artifact, dict) or max_chars <= 0:
+        return None
+    payload = artifact.get("knowledge_sources")
+    if not isinstance(payload, dict) or payload.get("version") != 1 or not isinstance(payload.get("sources"), list):
+        return None
+    sources = []
+    seen = set()
+    for source in payload["sources"][:100]:
+        if not isinstance(source, dict):
+            continue
+        source_id = source.get("id")
+        if not isinstance(source_id, str) or not re.fullmatch(r"[a-f0-9]{32}-[1-9][0-9]{0,2}", source_id):
+            continue
+        if source_id in seen or f"](#knowledge-{source_id})" not in content:
+            continue
+        if source.get("provider") != "ragflow" or not all(isinstance(source.get(field), str) for field in ("text", "dataset_name", "document_name")):
+            continue
+        seen.add(source_id)
+        sources.append(source)
+    if not sources:
+        return None
+
+    notice = "Knowledge sources omitted to fit output budget; request smaller excerpts."
+    # Remove old destinations before shortening the report, including any link
+    # fragments left by the generic synopsis/truncation transform.
+    summary = re.sub(r"\[([^\]\n]*)\]\(#(?:user-content-)?knowledge-[^)\s]*\)", r"\1", summary)
+    summary = re.sub(r"#(?:user-content-)?knowledge-[\w-]*", "", summary)
+    summary_limit = min(1000, max_chars // 4) if max_chars >= 160 else 0
+    if not summary_limit:
+        summary = ""
+    elif len(summary) > summary_limit:
+        # Keep the synopsis tail too: it can contain the read_file reference
+        # for the full externalized task report.
+        head = (summary_limit - 3) // 2
+        summary = summary[:head] + "\n…\n" + summary[-(summary_limit - head - 3) :]
+    summary = summary.rstrip()
+    entries = [summary] if summary else []
+    used = len(summary)
+    retained = []
+    for source in sources:
+        entry = f"[citation:{len(retained) + 1}](#knowledge-{source['id']}) {source['dataset_name']} / {source['document_name']}\n{source['text']}"
+        cost = len(entry) + (2 if entries else 0)
+        # Reserve a complete omission notice; never emit a partial source link.
+        if used + cost + len(notice) + 2 > max_chars:
+            continue
+        entries.append(entry)
+        used += cost
+        retained.append(source)
+    if len(retained) != len(sources):
+        entries.append(notice[:max_chars])
+    updated = dict(artifact)
+    if retained:
+        updated["knowledge_sources"] = {**payload, "sources": retained}
+    else:
+        updated.pop("knowledge_sources", None)
+    return "\n\n".join(entries), updated or None
+
+
+def cited_source_artifact(messages: list[dict[str, Any]], content: str) -> dict[str, Any] | None:
+    """Carry only actual captured sources cited in the child's final result."""
+    sources: dict[str, dict[str, Any]] = {}
+    remaining = 1_000_000
+    for message in messages:
+        if message.get("type") != "tool" or message.get("name") not in {"knowledge_search", "task"}:
+            continue
+        artifact = message.get("artifact")
+        payload = artifact.get("knowledge_sources") if isinstance(artifact, Mapping) else None
+        if not isinstance(payload, Mapping) or payload.get("version") != 1:
+            continue
+        raw_sources = payload.get("sources")
+        if not isinstance(raw_sources, list):
+            continue
+        for source in raw_sources[:100]:
+            if not isinstance(source, dict):
+                continue
+            source_id = source.get("id")
+            text = source.get("text")
+            if not isinstance(source_id, str) or not isinstance(text, str) or f"](#knowledge-{source_id})" not in content:
+                continue
+            if source_id in sources:
+                continue
+            if len(sources) >= 100 or len(text) > remaining:
+                continue
+            sources[source_id] = dict(source)
+            remaining -= len(text)
+    return {"knowledge_sources": {"version": 1, "sources": list(sources.values())}} if sources else None
diff --git a/backend/packages/harness/deerflow/community/ragflow/tools.py b/backend/packages/harness/deerflow/community/ragflow/tools.py
index 31e6bf76f..2836472b2 100644
--- a/backend/packages/harness/deerflow/community/ragflow/tools.py
+++ b/backend/packages/harness/deerflow/community/ragflow/tools.py
@@ -21,7 +21,7 @@ from deerflow.knowledge_scope import (
 from deerflow.tools.types import Runtime
 
 from .client import RAGFlowAPIError, RAGFlowClient, RAGFlowConnectionError, RAGFlowProtocolError
-from .formatting import format_retrieval_result
+from .formatting import format_retrieval_result, format_retrieval_sources
 
 logger = logging.getLogger(__name__)
 
@@ -516,6 +516,7 @@ async def knowledge_search(
     *,
     knowledge_scope: object | None = None,
     runtime: Runtime | None = None,
+    _source_artifact: dict[str, Any] | None = None,
 ) -> str:
     """Search the configured RAGFlow scope, defaulting to every accessible dataset."""
     query = query.strip()
@@ -564,6 +565,17 @@ async def knowledge_search(
 
         result = await _retrieve_dataset_groups(client, settings, query, groups)
         names_by_id = {dataset.dataset_id: dataset.name for dataset in datasets}
+        if _source_artifact is not None:
+            content, artifact = format_retrieval_sources(
+                result,
+                dataset_names_by_id=names_by_id,
+                max_chars_per_chunk=settings.max_chars_per_chunk,
+                max_total_chars=settings.max_total_chars,
+                redact=lambda value: _redact_api_key(value, _api_key(settings)),
+            )
+            if artifact is not None:
+                _source_artifact.update(artifact)
+            return content
         formatted = format_retrieval_result(
             result,
             dataset_names_by_id=names_by_id,
@@ -600,21 +612,28 @@ async def list_knowledge_bases() -> str:
 
 def _tool_description() -> str:
     base = "Search the operator-approved RAGFlow datasets and return compact, citation-numbered source chunks."
-    return f"{base} If knowledge_search.datasets is omitted, all datasets accessible to the configured RAGFlow API key are searched. Dataset IDs are never shown to the model."
+    return (
+        f"{base} If knowledge_search.datasets is omitted, all datasets accessible to the configured RAGFlow API key are searched. "
+        "Dataset IDs are never shown to the model. When citing results, copy the supplied [citation:N](#knowledge-...) links exactly; "
+        "do not invent or renumber source links."
+    )
 
 
-async def _knowledge_search_entrypoint(query: str, runtime: Runtime) -> str:
+async def _knowledge_search_entrypoint(query: str, runtime: Runtime) -> tuple[str, dict[str, Any] | None]:
     """Search the configured RAGFlow datasets, or every accessible dataset by default.
 
     Args:
         query: Specific question or search terms to retrieve from the configured private documents.
     """
-    return await knowledge_search(query, runtime=runtime)
+    artifact: dict[str, Any] = {}
+    content = await knowledge_search(query, runtime=runtime, _source_artifact=artifact)
+    return content, artifact or None
 
 
 knowledge_search_tool = StructuredTool.from_function(
     coroutine=_knowledge_search_entrypoint,
     name="knowledge_search",
+    response_format="content_and_artifact",
     description=_tool_description(),
     parse_docstring=True,
 )
diff --git a/backend/packages/harness/deerflow/tools/AGENTS.md b/backend/packages/harness/deerflow/tools/AGENTS.md
index 7d8e822e8..2aa6281bf 100644
--- a/backend/packages/harness/deerflow/tools/AGENTS.md
+++ b/backend/packages/harness/deerflow/tools/AGENTS.md
@@ -54,3 +54,9 @@ E2B output sync records remote file versions and actual host file metadata in a
 - ACP results collect only `agent_message_chunk` text. Thought chunks remain internal and must not be concatenated into the tool result
 - Missing ACP executables now return an actionable error message instead of a raw `[Errno 2]`
 - Each ACP agent uses a per-thread workspace at `{base_dir}/users/{user_id}/threads/{thread_id}/acp-workspace/`. The workspace is accessible to the lead agent via the virtual path `/mnt/acp-workspace/` (read-only). In docker sandbox mode, the directory is volume-mounted into the container at `/mnt/acp-workspace` (read-only); in local sandbox mode, path translation is handled by `tools.py`
+
+Ordinary `task` results forward bounded `artifact.knowledge_sources` records
+from captured child tool messages only when the final/partial report cites those
+opaque source links. This preserves retrieval evidence across the delegation
+boundary without placing provider IDs in model-visible text. Never reconstruct
+source records from the child's prose or replace them with fresh provider reads.
diff --git a/backend/packages/harness/deerflow/tools/builtins/task_tool.py b/backend/packages/harness/deerflow/tools/builtins/task_tool.py
index be5990b75..d68b801cd 100644
--- a/backend/packages/harness/deerflow/tools/builtins/task_tool.py
+++ b/backend/packages/harness/deerflow/tools/builtins/task_tool.py
@@ -19,6 +19,7 @@ from langgraph.types import Command
 
 from deerflow.agents.middlewares.receipt_verification import verify_receipt_citations
 from deerflow.authz.principal import normalize_authz_attributes
+from deerflow.community.ragflow.sources import cited_source_artifact
 from deerflow.config import get_app_config
 from deerflow.extensions import resolve_run_extensions
 from deerflow.knowledge_scope import KNOWLEDGE_SCOPE_RUNTIME_KEY, execution_scope
@@ -616,6 +617,7 @@ def _task_result_command(
     model_name: str | None = None,
     usage: dict[str, int] | None = None,
     tool_receipts: list[dict] | None = None,
+    source_messages: list[dict] | None = None,
     receipt_verdict: dict | None = None,
     acceptance_verdict: dict | None = None,
 ) -> Command:
@@ -631,6 +633,7 @@ def _task_result_command(
                     content=content,
                     tool_call_id=tool_call_id,
                     name="task",
+                    artifact=cited_source_artifact(source_messages or [], content),
                     additional_kwargs=make_subagent_additional_kwargs(
                         status,
                         result=result,
@@ -1089,6 +1092,7 @@ async def task_tool(
                     model_name=effective_model,
                     usage=usage,
                     tool_receipts=receipts,
+                    source_messages=getattr(result, "ai_messages", None),
                     receipt_verdict=receipt_verdict,
                     acceptance_verdict=acceptance_verdict,
                 )
@@ -1117,6 +1121,7 @@ async def task_tool(
                     model_name=effective_model,
                     usage=usage,
                     tool_receipts=getattr(result, "tool_receipts", None),
+                    source_messages=getattr(result, "ai_messages", None),
                 )
             elif result.status == SubagentStatus.CANCELLED:
                 _report_subagent_usage(runtime, result)
@@ -1139,6 +1144,7 @@ async def task_tool(
                     model_name=effective_model,
                     usage=usage,
                     tool_receipts=getattr(result, "tool_receipts", None),
+                    source_messages=getattr(result, "ai_messages", None),
                 )
             elif result.status == SubagentStatus.TIMED_OUT:
                 _report_subagent_usage(runtime, result)
@@ -1161,6 +1167,7 @@ async def task_tool(
                     model_name=effective_model,
                     usage=usage,
                     tool_receipts=getattr(result, "tool_receipts", None),
+                    source_messages=getattr(result, "ai_messages", None),
                 )
 
             # Still running, wait before next poll
@@ -1197,6 +1204,7 @@ async def task_tool(
                     model_name=effective_model,
                     usage=usage,
                     tool_receipts=getattr(result, "tool_receipts", None),
+                    source_messages=getattr(result, "ai_messages", None),
                 )
     except asyncio.CancelledError:
         # Signal the background subagent thread to stop cooperatively, then
diff --git a/backend/tests/test_agent_guidance_check.py b/backend/tests/test_agent_guidance_check.py
index 8dbc866a0..af1c07e4b 100644
--- a/backend/tests/test_agent_guidance_check.py
+++ b/backend/tests/test_agent_guidance_check.py
@@ -18,6 +18,7 @@ EXPECTED_GUIDANCE_PATHS = {
     "backend/packages/harness/deerflow/agents/AGENTS.md",
     "backend/packages/harness/deerflow/agents/middlewares/AGENTS.md",
     "backend/packages/harness/deerflow/agents/memory/AGENTS.md",
+    "backend/packages/harness/deerflow/community/ragflow/AGENTS.md",
     "backend/packages/harness/deerflow/community/tavily/AGENTS.md",
     "backend/packages/harness/deerflow/config/AGENTS.md",
     "backend/packages/harness/deerflow/extensions/AGENTS.md",
diff --git a/backend/tests/test_knowledge_citation_budget.py b/backend/tests/test_knowledge_citation_budget.py
new file mode 100644
index 000000000..685e145e0
--- /dev/null
+++ b/backend/tests/test_knowledge_citation_budget.py
@@ -0,0 +1,127 @@
+"""Citation records and model-visible evidence must stay paired after budgeting."""
+
+from copy import deepcopy
+from types import SimpleNamespace
+
+import pytest
+from langchain_core.messages import ToolMessage
+from langgraph.types import Command
+
+from deerflow.agents.middlewares.tool_output_budget_middleware import ToolOutputBudgetMiddleware, _patch_model_messages, _patch_result
+from deerflow.community.ragflow.formatting import format_retrieval_sources
+from deerflow.community.ragflow.sources import budget_source_artifact
+from deerflow.config.tool_output_config import ToolOutputConfig
+
+
+def message(name="knowledge_search"):
+    chunks = [{"id": f"chunk-{i}", "dataset_id": "kb", "document_id": "doc", "document_keyword": "Manual.pdf", "content": f"Evidence {i}: " + "x" * 4800} for i in range(8)]
+    content, artifact = format_retrieval_sources({"chunks": chunks}, dataset_names_by_id={"kb": "Engineering"}, max_chars_per_chunk=5000, max_total_chars=40000)
+    if name == "task":
+        links = " ".join(f"[Manual.pdf](#knowledge-{source['id']})" for source in artifact["knowledge_sources"]["sources"])
+        content = "Task completed. Findings: " + links + "\n" + "report " * 6000
+    artifact["other"] = "preserve me"
+    return ToolMessage(content=content, artifact=artifact, name=name, tool_call_id="call-1")
+
+
+def assert_paired(original, result, limit):
+    assert len(result.content) <= limit
+    assert result.artifact["other"] == "preserve me"
+    sources = result.artifact.get("knowledge_sources", {}).get("sources", [])
+    assert sources
+    assert len(sources) < len(original.artifact["knowledge_sources"]["sources"])
+    for source in original.artifact["knowledge_sources"]["sources"]:
+        if source in sources:
+            assert f"](#knowledge-{source['id']})" in result.content
+            assert source["text"] in result.content
+        else:
+            assert f"#knowledge-{source['id']}" not in result.content
+    assert "omitted" in result.content
+
+
+@pytest.mark.parametrize("name", ["knowledge_search", "task"])
+@pytest.mark.parametrize("mode", ["externalize", "fallback", "override", "history", "no_storage"])
+def test_complete_citations_survive_budget_paths(tmp_path, name, mode):
+    original = message(name)
+    snapshot = deepcopy(original)
+    limit = 12000 if mode == "externalize" else 7000
+    config = ToolOutputConfig(**({"fallback_max_chars": limit, "externalize_min_chars": 0} if mode in {"fallback", "history"} else {"tool_overrides": {name: limit}}))
+    if mode == "history":
+        result = _patch_model_messages([original], config)[0]
+    else:
+        command = Command(update={"messages": [original], "unrelated": 42})
+        patched = _patch_result(command, config, str(tmp_path) if mode not in {"fallback", "no_storage"} else None)
+        assert patched.update["unrelated"] == 42
+        result = patched.update["messages"][0]
+    assert_paired(original, result, limit)
+    assert original == snapshot
+    transforms = result.additional_kwargs["deerflow_tool_transforms"]
+    assert transforms[-1]["kind"] == "truncated"
+    if mode in {"externalize", "override"}:
+        assert transforms[-2]["kind"] == "externalized"
+    # A subsequent model hook must not rewrite the same evidence again.
+    assert _patch_model_messages([result], config) is None
+
+
+@pytest.mark.parametrize("name", ["knowledge_search", "task"])
+@pytest.mark.parametrize("limit", [1, 60, 159, 160, 500])
+def test_tiny_budget_does_not_leave_orphaned_or_partial_citations(name, limit):
+    original = message(name)
+    config = ToolOutputConfig(externalize_min_chars=0, fallback_max_chars=limit)
+    result = _patch_result(original, config, None)
+    assert len(result.content) <= limit
+    assert "#knowledge-" not in result.content
+    assert "knowledge_sources" not in result.artifact
+    assert result.artifact["other"] == "preserve me"
+
+
+@pytest.mark.parametrize("config", [ToolOutputConfig(enabled=False), ToolOutputConfig(exempt_tools=["knowledge_search"]), ToolOutputConfig(externalize_min_chars=0, fallback_max_chars=0)])
+def test_disabled_and_exempt_budget_preserves_sources(config):
+    original = message()
+    request = SimpleNamespace(tool_call={"name": "knowledge_search", "id": "call-1"}, runtime=SimpleNamespace(state={}))
+    result = ToolOutputBudgetMiddleware(config).wrap_tool_call(request, lambda _: original)
+    assert result is original
+
+
+@pytest.mark.asyncio
+async def test_async_tool_hook_preserves_sources():
+    original = message()
+    request = SimpleNamespace(tool_call={"name": "knowledge_search", "id": "call-1"}, runtime=SimpleNamespace(state={}))
+
+    async def handler(_):
+        return original
+
+    result = await ToolOutputBudgetMiddleware(ToolOutputConfig(externalize_min_chars=0, fallback_max_chars=7000)).awrap_tool_call(request, handler)
+    assert_paired(original, result, 7000)
+
+
+@pytest.mark.parametrize("change", ["other_tool", "unknown_version", "malformed_records", "no_artifact"])
+def test_unrelated_results_keep_the_generic_budget_behavior(change):
+    original = message()
+    if change == "other_tool":
+        original.name = "web_search"
+    elif change == "unknown_version":
+        original.artifact["knowledge_sources"]["version"] = 2
+    elif change == "malformed_records":
+        original.artifact["knowledge_sources"]["sources"] = [None, {"id": "invalid", "text": 42}]
+    else:
+        original.artifact = None
+    config = ToolOutputConfig(externalize_min_chars=0, fallback_max_chars=7000)
+    control = _patch_result(original.model_copy(update={"artifact": None}), config, None)
+    result = _patch_result(original, config, None)
+    assert result.content == control.content
+    assert result.artifact == original.artifact
+
+
+def test_small_source_result_is_not_rewritten():
+    original = message()
+    config = ToolOutputConfig(externalize_min_chars=50000, fallback_max_chars=50000)
+    assert _patch_result(original, config, None) is original
+
+
+def test_delegated_budget_retains_the_report_reference_and_complete_evidence():
+    original = message("task")
+    summary = "Task completed. " + "synopsis " * 500 + "\nRead the full report: /mnt/user-data/outputs/.tool-results/report.txt"
+    content, artifact = budget_source_artifact(original.content, original.artifact, 7000, summary=summary)
+    assert content.startswith("Task completed.")
+    assert "/mnt/user-data/outputs/.tool-results/report.txt" in content
+    assert_paired(original, original.model_copy(update={"content": content, "artifact": artifact}), 7000)
diff --git a/backend/tests/test_ragflow_tools.py b/backend/tests/test_ragflow_tools.py
index a54777cb2..ff561d3be 100644
--- a/backend/tests/test_ragflow_tools.py
+++ b/backend/tests/test_ragflow_tools.py
@@ -1065,3 +1065,98 @@ def test_ragflow_package_has_explicit_init_file() -> None:
     package_dir = Path(ragflow_tools.__file__).resolve().parent
 
     assert (package_dir / "__init__.py").is_file()
+
+
+@pytest.mark.asyncio
+async def test_search_artifact_binds_citation_to_exact_retrieved_document(monkeypatch: pytest.MonkeyPatch) -> None:
+    client = FakeRAGFlowClient(
+        all_datasets=[_dataset(DATASET_ID_1, "Engineering")],
+        retrieval={"chunks": [{"id": "chunk-a", "dataset_id": DATASET_ID_1, "document_id": "doc-a", "document_keyword": "Manual.pdf", "content": "The limit is 42.", "positions": [[3, 10, 20, 30, 40]]}]},
+    )
+    monkeypatch.setattr(ragflow_tools, "get_app_config", lambda: _config())
+    monkeypatch.setattr(ragflow_tools, "_build_client", lambda _: client)
+    runtime = SimpleNamespace(context={})
+    content, artifact = await ragflow_tools._knowledge_search_entrypoint("limit", runtime)
+    source = artifact["knowledge_sources"]["sources"][0]
+    assert source["document_id"] == "doc-a"
+    assert source["chunk_id"] == "chunk-a"
+    assert source["document_name"] == "Manual.pdf"
+    assert source["text"] == "The limit is 42."
+    assert source["pages"] == [3]
+    assert f"](#knowledge-{source['id']})" in content
+    assert DATASET_ID_1 not in content
+    assert "doc-a" not in content
+    _, next_artifact = await ragflow_tools._knowledge_search_entrypoint("limit", runtime)
+    assert next_artifact["knowledge_sources"]["sources"][0]["id"] != source["id"]
+
+
+@pytest.mark.asyncio
+async def test_search_artifact_redacts_credentials_and_has_no_sources_on_error(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(ragflow_tools, "get_app_config", lambda: _config())
+    client = FakeRAGFlowClient(
+        all_datasets=[_dataset(DATASET_ID_1, "ragflow-secret")],
+        retrieval={"chunks": [{"id": "chunk-a", "dataset_id": DATASET_ID_1, "document_id": "doc-a", "document_keyword": "ragflow-secret", "content": "ragflow-secret"}]},
+    )
+    monkeypatch.setattr(ragflow_tools, "_build_client", lambda _: client)
+    result = await ragflow_tools._knowledge_search_entrypoint("query", SimpleNamespace(context={}))
+    assert "ragflow-secret" not in str(result)
+    content, artifact = await ragflow_tools._knowledge_search_entrypoint("", SimpleNamespace(context={}))
+    assert content.startswith("Error:")
+    assert artifact is None
+
+
+@pytest.mark.asyncio
+async def test_citation_artifact_survives_native_tool_node_and_message_serialization(monkeypatch: pytest.MonkeyPatch) -> None:
+    from langchain_core.messages import AIMessage, messages_from_dict, messages_to_dict
+    from langgraph.graph import END, START, MessagesState, StateGraph
+    from langgraph.prebuilt import ToolNode
+
+    client = FakeRAGFlowClient(
+        all_datasets=[_dataset(DATASET_ID_1, "Engineering")],
+        retrieval={"chunks": [{"id": "chunk-a", "dataset_id": DATASET_ID_1, "document_id": "doc-a", "document_keyword": "Manual.pdf", "content": "Limit: 42."}]},
+    )
+    monkeypatch.setattr(ragflow_tools, "get_app_config", lambda: _config())
+    monkeypatch.setattr(ragflow_tools, "_build_client", lambda _: client)
+    builder = StateGraph(MessagesState)
+    builder.add_node("tools", ToolNode([ragflow_tools.knowledge_search_tool]))
+    builder.add_edge(START, "tools")
+    builder.add_edge("tools", END)
+    result = await builder.compile().ainvoke({"messages": [AIMessage(content="", tool_calls=[{"name": "knowledge_search", "args": {"query": "limit"}, "id": "call-a"}])]})
+    tool_message = result["messages"][-1]
+    assert tool_message.status == "success"
+    assert tool_message.artifact["knowledge_sources"]["sources"][0]["document_id"] == "doc-a"
+    restored = messages_from_dict(messages_to_dict([tool_message]))[0]
+    assert restored.artifact == tool_message.artifact
+    assert restored.content == tool_message.content
+
+
+def test_subagent_forwards_only_cited_captured_sources() -> None:
+    from deerflow.community.ragflow.sources import cited_source_artifact
+
+    sources = [{"id": "a", "text": "first"}, {"id": "b", "text": "second"}]
+    messages = [{"type": "tool", "name": "knowledge_search", "artifact": {"knowledge_sources": {"version": 1, "sources": sources}}}]
+    assert cited_source_artifact(messages, "[citation:1](#knowledge-a)") == {"knowledge_sources": {"version": 1, "sources": [sources[0]]}}
+    assert cited_source_artifact(messages, "[citation:3](#knowledge-invented)") is None
+    assert cited_source_artifact([{**messages[0], "type": "ai"}], "[citation:1](#knowledge-a)") is None
+
+
+def test_citation_budget_never_emits_partial_links_or_unseen_artifact_text() -> None:
+    from deerflow.community.ragflow.formatting import format_retrieval_sources
+
+    chunks = [{"id": f"chunk-{i}", "dataset_id": DATASET_ID_1, "document_id": "doc", "content": "X" * 1000} for i in range(4)]
+    content, artifact = format_retrieval_sources({"chunks": chunks}, dataset_names_by_id={DATASET_ID_1: "Knowledge"}, max_total_chars=200, max_chars_per_chunk=100)
+    assert len(content) <= 200
+    sources = artifact["knowledge_sources"]["sources"]
+    assert len(sources) == 1
+    assert f"](#knowledge-{sources[0]['id']})" in content
+    assert sources[0]["text"] in content
+    assert sources[0]["truncated"] is True
+
+
+def test_task_command_preserves_child_source_artifact() -> None:
+    from deerflow.tools.builtins.task_tool import _task_result_command
+
+    source = {"id": "abc", "text": "evidence"}
+    message = {"type": "tool", "name": "knowledge_search", "artifact": {"knowledge_sources": {"version": 1, "sources": [source]}}}
+    command = _task_result_command(tool_call_id="task-1", status="completed", result="Answer [citation:1](#knowledge-abc)", source_messages=[message])
+    assert command.update["messages"][0].artifact["knowledge_sources"]["sources"] == [source]
diff --git a/docs/pr-evidence/knowledge-citations-desktop.png b/docs/pr-evidence/knowledge-citations-desktop.png
new file mode 100644
index 000000000..c18752ac4
Binary files /dev/null and b/docs/pr-evidence/knowledge-citations-desktop.png differ
diff --git a/docs/pr-evidence/knowledge-citations-mobile.png b/docs/pr-evidence/knowledge-citations-mobile.png
new file mode 100644
index 000000000..912387bcf
Binary files /dev/null and b/docs/pr-evidence/knowledge-citations-mobile.png differ
diff --git a/frontend/src/AGENTS.md b/frontend/src/AGENTS.md
index f543920e3..25fbb836d 100644
--- a/frontend/src/AGENTS.md
+++ b/frontend/src/AGENTS.md
@@ -190,3 +190,15 @@ association and usage accounting, but renders text accompanying
 message grouping. Incremental prefix/tail splitting applies only at human
 boundaries; clarification results also belong to the preceding processing group,
 so derive the full grouping and stabilize references at clarification boundaries.
+
+### Knowledge source citations
+
+`KnowledgeSourcesProvider` scopes source records to the current message list.
+Only versioned native `knowledge_search`/`task` tool artifacts supply evidence;
+AI/human text and metadata cannot create a source. `CitationLink` resolves
+`#knowledge-…` citations through that context and renders unavailable text when
+there is no matching record. `KnowledgeSourcesPanel` lists only sources cited
+outside code/images. Dialog excerpts render as plain text, never HTML or nested
+Markdown. Source records retain retrieval-time evidence, not live documents.
+Resolve knowledge destinations before testing the label in message and artifact
+link renderers: Sources lists use ordinary titles without a `citation:` prefix.
diff --git a/frontend/src/components/workspace/citations/artifact-link.tsx b/frontend/src/components/workspace/citations/artifact-link.tsx
index 1560c3086..105d30d69 100644
--- a/frontend/src/components/workspace/citations/artifact-link.tsx
+++ b/frontend/src/components/workspace/citations/artifact-link.tsx
@@ -1,5 +1,6 @@
 import type { AnchorHTMLAttributes } from "react";
 
+import { knowledgeSourceId } from "@/core/knowledge/sources";
 import { cn } from "@/lib/utils";
 
 import { isSafeHref, UnsafeLink } from "../messages/markdown-link";
@@ -10,7 +11,7 @@ function isExternalUrl(href: string | undefined): boolean {
   return !!href && /^https?:\/\//.test(href);
 }
 
-/** Link renderer for artifact markdown: citation: prefix → CitationLink, otherwise underlined text. */
+/** Knowledge destinations and citation-prefixed links use the source renderer. */
 export function ArtifactLink(props: AnchorHTMLAttributes<HTMLAnchorElement>) {
   // Reject unsafe schemes so prompt-injected [label](javascript:...) in a .md
   // artifact preview cannot execute in the main document, matching the guard in
@@ -26,6 +27,9 @@ export function ArtifactLink(props: AnchorHTMLAttributes<HTMLAnchorElement>) {
       </UnsafeLink>
     );
   }
+  if (knowledgeSourceId(props.href)) {
+    return <CitationLink {...props} />;
+  }
   const childrenText = extractReactNodeText(props.children);
   if (childrenText !== null) {
     const match = /^citation:(.+)$/.exec(childrenText);
diff --git a/frontend/src/components/workspace/citations/citation-link.tsx b/frontend/src/components/workspace/citations/citation-link.tsx
index 40c3c3064..ff5fcf2c2 100644
--- a/frontend/src/components/workspace/citations/citation-link.tsx
+++ b/frontend/src/components/workspace/citations/citation-link.tsx
@@ -9,6 +9,8 @@ import {
 } from "@/components/ui/hover-card";
 import { cn } from "@/lib/utils";
 
+import { KnowledgeCitationLink } from "./knowledge-source";
+
 /** Extract visible text from renderer-provided ReactNode children. */
 export function extractReactNodeText(node: ReactNode): string | null {
   if (typeof node === "string" || typeof node === "number") {
@@ -41,6 +43,12 @@ export function CitationLink({
   const isGenericText = childrenText === "Source" || childrenText === "来源";
   const displayText = (!isGenericText && childrenText) ?? domain;
 
+  if (href && /^#(?:user-content-)?knowledge-/.test(href)) {
+    return (
+      <KnowledgeCitationLink href={href}>{displayText}</KnowledgeCitationLink>
+    );
+  }
+
   return (
     <HoverCard closeDelay={0} openDelay={0}>
       <HoverCardTrigger asChild>
diff --git a/frontend/src/components/workspace/citations/knowledge-source.tsx b/frontend/src/components/workspace/citations/knowledge-source.tsx
new file mode 100644
index 000000000..03f08b432
--- /dev/null
+++ b/frontend/src/components/workspace/citations/knowledge-source.tsx
@@ -0,0 +1,153 @@
+"use client";
+
+import type { Message } from "@langchain/langgraph-sdk";
+import { BookOpenTextIcon } from "lucide-react";
+import { createContext, useContext, useMemo, type ReactNode } from "react";
+
+import { Badge } from "@/components/ui/badge";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogHeader,
+  DialogTitle,
+  DialogTrigger,
+} from "@/components/ui/dialog";
+import { useI18n } from "@/core/i18n/hooks";
+import {
+  citedKnowledgeSources,
+  collectKnowledgeSources,
+  knowledgeSourceId,
+  type KnowledgeSource,
+} from "@/core/knowledge/sources";
+
+const SourcesContext = createContext<ReadonlyMap<string, KnowledgeSource>>(
+  new Map(),
+);
+
+export function KnowledgeSourcesProvider({
+  messages,
+  children,
+}: {
+  messages: readonly Message[];
+  children: ReactNode;
+}) {
+  const sources = useMemo(() => collectKnowledgeSources(messages), [messages]);
+  return (
+    <SourcesContext.Provider value={sources}>
+      {children}
+    </SourcesContext.Provider>
+  );
+}
+
+function SourceDialog({
+  source,
+  children,
+}: {
+  source: KnowledgeSource;
+  children: ReactNode;
+}) {
+  const { t } = useI18n();
+  return (
+    <Dialog>
+      <DialogTrigger asChild>
+        <button
+          type="button"
+          className="text-left"
+          aria-label={t.citations.viewKnowledgeSource(source.document_name)}
+          onClick={(event) => event.stopPropagation()}
+        >
+          {children}
+        </button>
+      </DialogTrigger>
+      <DialogContent className="max-h-[85dvh] overflow-y-auto sm:max-w-2xl">
+        <DialogHeader>
+          <DialogTitle className="break-words">
+            {source.document_name}
+          </DialogTitle>
+          <DialogDescription>
+            {source.dataset_name}
+            {source.pages.length > 0
+              ? ` · ${t.citations.sourcePages(source.pages.join(", "))}`
+              : ""}
+          </DialogDescription>
+        </DialogHeader>
+        <p className="text-muted-foreground text-xs">
+          {t.citations.retrievedExcerpt}
+        </p>
+        <blockquote className="border-primary/30 border-l-2 pl-4 text-sm leading-relaxed break-words whitespace-pre-wrap">
+          {source.text}
+        </blockquote>
+        {source.truncated && (
+          <p className="text-muted-foreground text-xs">
+            {t.citations.excerptTruncated}
+          </p>
+        )}
+      </DialogContent>
+    </Dialog>
+  );
+}
+
+export function KnowledgeCitationLink({
+  href,
+  children,
+}: {
+  href: string;
+  children: ReactNode;
+}) {
+  const sources = useContext(SourcesContext);
+  const { t } = useI18n();
+  const id = knowledgeSourceId(href);
+  const source = id ? sources.get(id) : undefined;
+  if (!source)
+    return (
+      <span
+        className="text-muted-foreground"
+        title={t.citations.sourceUnavailable}
+      >
+        {children}
+      </span>
+    );
+  return (
+    <SourceDialog source={source}>
+      <Badge
+        variant="secondary"
+        className="mx-0.5 cursor-pointer gap-1 rounded-full px-2 py-0.5 text-xs font-normal"
+      >
+        <BookOpenTextIcon className="size-3" />
+        {children}
+      </Badge>
+    </SourceDialog>
+  );
+}
+
+export function KnowledgeSourcesPanel({ content }: { content: string }) {
+  const allSources = useContext(SourcesContext);
+  const { t } = useI18n();
+  const sources = useMemo(
+    () => citedKnowledgeSources(content, allSources),
+    [content, allSources],
+  );
+  if (sources.length === 0) return null;
+  return (
+    <details className="not-prose border-border/60 bg-muted/20 mt-2 rounded-md border text-xs">
+      <summary className="text-muted-foreground cursor-pointer px-3 py-2">
+        {t.citations.knowledgeSourcesSummary(sources.length)}
+      </summary>
+      <ul className="border-border/60 max-h-80 space-y-2 overflow-y-auto border-t p-3">
+        {sources.map((source) => (
+          <li key={source.id}>
+            <SourceDialog source={source}>
+              <span className="text-foreground block font-medium break-words">
+                {source.document_name}
+              </span>
+              <span className="text-muted-foreground block break-words">
+                {source.dataset_name}
+              </span>
+            </SourceDialog>
+          </li>
+        ))}
+      </ul>
+    </details>
+  );
+}
diff --git a/frontend/src/components/workspace/messages/markdown-link.tsx b/frontend/src/components/workspace/messages/markdown-link.tsx
index 07fdd64af..7ed34b306 100644
--- a/frontend/src/components/workspace/messages/markdown-link.tsx
+++ b/frontend/src/components/workspace/messages/markdown-link.tsx
@@ -1,6 +1,7 @@
 import type { AnchorHTMLAttributes, ComponentProps } from "react";
 
 import { resolveMarkdownArtifactURL } from "@/core/artifacts/utils";
+import { knowledgeSourceId } from "@/core/knowledge/sources";
 import { cn } from "@/lib/utils";
 
 import { CitationLink, extractReactNodeText } from "../citations/citation-link";
@@ -107,6 +108,10 @@ export function createMarkdownLinkComponent(threadId?: string) {
         </UnsafeLink>
       );
     }
+    // Knowledge destinations also appear as ordinary [Title](URL) Sources links.
+    if (knowledgeSourceId(href)) {
+      return <CitationLink {...props} href={href} />;
+    }
     // Safe-href check passed — citation links now route through CitationLink.
     const childrenText = extractReactNodeText(props.children);
     if (childrenText !== null) {
diff --git a/frontend/src/components/workspace/messages/message-list-item.tsx b/frontend/src/components/workspace/messages/message-list-item.tsx
index 9ec0526e0..933949cc9 100644
--- a/frontend/src/components/workspace/messages/message-list-item.tsx
+++ b/frontend/src/components/workspace/messages/message-list-item.tsx
@@ -63,6 +63,7 @@ import { cn } from "@/lib/utils";
 
 import { WorkspaceChangeBadge } from "../changes";
 import { CitationSourcesPanel } from "../citations/citation-sources-panel";
+import { KnowledgeSourcesPanel } from "../citations/knowledge-source";
 import { ConversationReferenceChip } from "../conversation-references/conversation-reference-chip";
 import { CopyButton } from "../copy-button";
 import { ReferenceAttachmentSummary } from "../sidecar/reference-attachments";
@@ -618,6 +619,7 @@ function MessageContent_({
         components={components}
       />
       <CitationSourcesPanel sources={citationSources} />
+      <KnowledgeSourcesPanel content={contentToDisplay} />
       {message.type === "ai" && showWorkspaceChanges && (
         <WorkspaceChangeBadge
           threadId={threadId}
diff --git a/frontend/src/components/workspace/messages/message-list.tsx b/frontend/src/components/workspace/messages/message-list.tsx
index ed31b25b6..407a36d17 100644
--- a/frontend/src/components/workspace/messages/message-list.tsx
+++ b/frontend/src/components/workspace/messages/message-list.tsx
@@ -25,6 +25,7 @@ import {
   type ConversationProps,
 } from "@/components/ai-elements/conversation";
 import { Button } from "@/components/ui/button";
+import { KnowledgeSourcesProvider } from "@/components/workspace/citations/knowledge-source";
 import { extractArtifactsFromThread } from "@/core/artifacts/utils";
 import { useI18n } from "@/core/i18n/hooks";
 import { getArtifactArchiveCandidatesByGroupIndex } from "@/core/messages/artifact-archive";
@@ -1078,7 +1079,7 @@ export function MessageList({
     );
   };
   return (
-    <>
+    <KnowledgeSourcesProvider messages={thread.messages}>
       <Conversation
         className={cn("flex size-full flex-col justify-center", className)}
         data-testid={testId}
@@ -1504,6 +1505,6 @@ export function MessageList({
           </Button>
         </div>
       )}
-    </>
+    </KnowledgeSourcesProvider>
   );
 }
diff --git a/frontend/src/core/citations/sources.ts b/frontend/src/core/citations/sources.ts
index e3c0fcdbd..123ed18ce 100644
--- a/frontend/src/core/citations/sources.ts
+++ b/frontend/src/core/citations/sources.ts
@@ -27,7 +27,7 @@ export function extractCitationSources(markdown: string): CitationSource[] {
     return [];
   }
 
-  const searchable = maskCode(markdown);
+  const searchable = maskCitationCode(markdown);
   const sourcesByUrl = new Map<string, CitationSource>();
 
   for (const match of searchable.matchAll(CITATION_LINK_RE)) {
@@ -99,7 +99,7 @@ function extractDomain(url: string): string {
 // Blanks out code regions so example citations inside code aren't scraped as
 // real sources, while preserving string length (and newlines) so occurrence
 // indices stay aligned with the original markdown.
-function maskCode(markdown: string): string {
+export function maskCitationCode(markdown: string): string {
   return maskInlineCode(maskFencedCodeBlocks(markdown));
 }
 
diff --git a/frontend/src/core/i18n/locales/en-US.ts b/frontend/src/core/i18n/locales/en-US.ts
index d8cb73d89..8f5ee0a31 100644
--- a/frontend/src/core/i18n/locales/en-US.ts
+++ b/frontend/src/core/i18n/locales/en-US.ts
@@ -218,6 +218,14 @@ export const enUS: Translations = {
 
   // Citations
   citations: {
+    viewKnowledgeSource: (title: string) => `View source: ${title}`,
+    sourcePages: (pages: string) => `Pages ${pages}`,
+    retrievedExcerpt:
+      "Evidence captured when this answer was researched. The source document may have changed since retrieval.",
+    excerptTruncated: "This excerpt was shortened to fit the retrieval limit.",
+    sourceUnavailable:
+      "Source evidence is unavailable in the loaded conversation.",
+    knowledgeSourcesSummary: (count: number) => `${count} knowledge sources`,
     sourcesSummary: (count) =>
       `Used ${count} ${count === 1 ? "source" : "sources"}`,
     citeCount: (count) => `${count} ${count === 1 ? "cite" : "cites"}`,
diff --git a/frontend/src/core/i18n/locales/types.ts b/frontend/src/core/i18n/locales/types.ts
index 7a36fe4c1..4d702ded8 100644
--- a/frontend/src/core/i18n/locales/types.ts
+++ b/frontend/src/core/i18n/locales/types.ts
@@ -185,6 +185,12 @@ export interface Translations {
 
   // Citations
   citations: {
+    viewKnowledgeSource: (title: string) => string;
+    sourcePages: (pages: string) => string;
+    retrievedExcerpt: string;
+    excerptTruncated: string;
+    sourceUnavailable: string;
+    knowledgeSourcesSummary: (count: number) => string;
     sourcesSummary: (count: number) => string;
     citeCount: (count: number) => string;
     copyReference: (title: string) => string;
diff --git a/frontend/src/core/i18n/locales/zh-CN.ts b/frontend/src/core/i18n/locales/zh-CN.ts
index 33e01f55f..b69e198f6 100644
--- a/frontend/src/core/i18n/locales/zh-CN.ts
+++ b/frontend/src/core/i18n/locales/zh-CN.ts
@@ -207,6 +207,13 @@ export const zhCN: Translations = {
 
   // Citations
   citations: {
+    viewKnowledgeSource: (title: string) => `查看来源：${title}`,
+    sourcePages: (pages: string) => `第 ${pages} 页`,
+    retrievedExcerpt:
+      "这是回答生成时检索到的证据片段，源文档此后可能已发生变化。",
+    excerptTruncated: "该片段已按检索长度限制截短。",
+    sourceUnavailable: "当前加载的对话中没有这条引用的来源记录。",
+    knowledgeSourcesSummary: (count: number) => `${count} 个知识库来源`,
     sourcesSummary: (count) => `使用了 ${count} 个来源`,
     citeCount: (count) => `${count} 次引用`,
     copyReference: (title) => `复制 ${title} 引用`,
diff --git a/frontend/src/core/knowledge/sources.ts b/frontend/src/core/knowledge/sources.ts
new file mode 100644
index 000000000..266798054
--- /dev/null
+++ b/frontend/src/core/knowledge/sources.ts
@@ -0,0 +1,107 @@
+import type { Message } from "@langchain/langgraph-sdk";
+
+import { maskCitationCode } from "@/core/citations/sources";
+
+export type KnowledgeSource = {
+  id: string;
+  provider: "ragflow";
+  dataset_name: string;
+  document_name: string;
+  text: string;
+  truncated: boolean;
+  pages: number[];
+};
+
+const SOURCE_ID = /^[a-f0-9]{32}-[1-9][0-9]{0,2}$/;
+const SOURCE_LINK =
+  /(?<!!)\[[^\]\n]+\]\(#(?:user-content-)?knowledge-([a-f0-9]{32}-[1-9][0-9]{0,2})\)/g;
+
+function record(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+/** Read only native tool artifacts, never model or human-provided metadata. */
+export function collectKnowledgeSources(messages: readonly Message[]) {
+  const sources = new Map<string, KnowledgeSource>();
+  for (const message of messages) {
+    if (
+      message.type !== "tool" ||
+      !["knowledge_search", "task"].includes(message.name ?? "")
+    )
+      continue;
+    const artifact: unknown = Reflect.get(message, "artifact");
+    const payload = record(artifact) ? artifact.knowledge_sources : null;
+    if (
+      !record(payload) ||
+      payload.version !== 1 ||
+      !Array.isArray(payload.sources)
+    )
+      continue;
+    for (const raw of payload.sources.slice(0, 100)) {
+      if (
+        !record(raw) ||
+        typeof raw.id !== "string" ||
+        !SOURCE_ID.test(raw.id) ||
+        raw.provider !== "ragflow"
+      )
+        continue;
+      if (
+        typeof raw.document_name !== "string" ||
+        raw.document_name.length > 1024 ||
+        typeof raw.dataset_name !== "string" ||
+        raw.dataset_name.length > 1024 ||
+        typeof raw.text !== "string" ||
+        raw.text.length > 200_000 ||
+        typeof raw.truncated !== "boolean" ||
+        !Array.isArray(raw.pages) ||
+        raw.pages.length > 100 ||
+        !raw.pages.every(
+          (page: unknown) =>
+            typeof page === "number" &&
+            Number.isInteger(page) &&
+            page > 0 &&
+            page <= 1_000_000,
+        )
+      )
+        continue;
+      const source: KnowledgeSource = {
+        id: raw.id,
+        provider: "ragflow",
+        dataset_name: raw.dataset_name,
+        document_name: raw.document_name,
+        text: raw.text,
+        truncated: raw.truncated,
+        pages: raw.pages as number[],
+      };
+      // Stream replays can repeat records; never silently replace evidence.
+      if (!sources.has(source.id)) sources.set(source.id, source);
+    }
+  }
+  return sources;
+}
+
+export function knowledgeSourceId(href: string | undefined): string | null {
+  // rehype-sanitize prefixes same-document anchors to prevent DOM clobbering.
+  const match =
+    /^#(?:user-content-)?knowledge-([a-f0-9]{32}-[1-9][0-9]{0,2})$/.exec(
+      href ?? "",
+    );
+  return match?.[1] ?? null;
+}
+
+export function citedKnowledgeSources(
+  markdown: string,
+  sources: ReadonlyMap<string, KnowledgeSource>,
+) {
+  const result: KnowledgeSource[] = [];
+  const seen = new Set<string>();
+  for (const match of maskCitationCode(markdown).matchAll(SOURCE_LINK)) {
+    const id = match[1]!;
+    const source = sources.get(id);
+    if (source && !seen.has(id)) {
+      seen.add(id);
+      result.push(source);
+    }
+  }
+  return result;
+}
diff --git a/frontend/tests/e2e/knowledge-citations.spec.ts b/frontend/tests/e2e/knowledge-citations.spec.ts
new file mode 100644
index 000000000..f65ccf9c2
--- /dev/null
+++ b/frontend/tests/e2e/knowledge-citations.spec.ts
@@ -0,0 +1,106 @@
+import { expect, test } from "@playwright/test";
+
+import { MOCK_THREAD_ID, mockLangGraphAPI } from "./utils/mock-api";
+
+const sourceId = "0123456789abcdef0123456789abcdef-1";
+const messages = [
+  { id: "human-1", type: "human", content: "What is the maximum pressure?" },
+  {
+    id: "ai-search",
+    type: "ai",
+    content: "",
+    tool_calls: [
+      {
+        id: "search-1",
+        name: "knowledge_search",
+        args: { query: "maximum pressure" },
+      },
+    ],
+  },
+  {
+    id: "tool-1",
+    type: "tool",
+    name: "knowledge_search",
+    tool_call_id: "search-1",
+    content: `[citation:1](#knowledge-${sourceId}) Engineering / Safety manual.pdf\nMaximum pressure: 42 kPa.`,
+    artifact: {
+      knowledge_sources: {
+        version: 1,
+        sources: [
+          {
+            id: sourceId,
+            provider: "ragflow",
+            dataset_name: "Engineering",
+            document_name: "Safety manual.pdf",
+            dataset_id: "dataset-a",
+            document_id: "doc-a",
+            chunk_id: "chunk-a",
+            text: "Maximum pressure: 42 kPa.\nInspect the seal before operation.",
+            pages: [3],
+            truncated: false,
+          },
+        ],
+      },
+    },
+  },
+  {
+    id: "answer-1",
+    type: "ai",
+    content: `The maximum pressure is **42 kPa**. [citation:1](#knowledge-${sourceId})\n\n## Sources\n- [Safety manual.pdf](#knowledge-${sourceId})`,
+  },
+];
+
+test("knowledge references open source evidence before and after history reload", async ({
+  page,
+}, testInfo) => {
+  mockLangGraphAPI(page, {
+    threads: [
+      {
+        thread_id: MOCK_THREAD_ID,
+        title: "Knowledge source verification",
+        messages,
+      },
+    ],
+  });
+  await page.goto(`/workspace/chats/${MOCK_THREAD_ID}`);
+  const source = page.getByRole("button", {
+    name: "View source: Safety manual.pdf",
+  });
+  await expect(source.first()).toBeVisible();
+  await source.first().click();
+  await expect(page.getByRole("dialog")).toContainText(
+    "Maximum pressure: 42 kPa.",
+  );
+  await expect(page.getByRole("dialog")).toContainText("Pages 3");
+  await expect(page.getByRole("dialog")).toHaveCSS("opacity", "1");
+  await page.screenshot({
+    path: testInfo.outputPath("knowledge-citation-desktop.png"),
+    fullPage: true,
+  });
+  await page
+    .getByRole("dialog")
+    .getByRole("button", { name: "Close", exact: true })
+    .click();
+  // Sources-section links have an ordinary title, without the citation prefix.
+  const titledSource = source.filter({ hasText: "Safety manual.pdf" }).first();
+  await titledSource.click();
+  await expect(page.getByRole("dialog")).toContainText(
+    "Maximum pressure: 42 kPa.",
+  );
+  await page
+    .getByRole("dialog")
+    .getByRole("button", { name: "Close", exact: true })
+    .click();
+  await page.reload();
+  await expect(source.first()).toBeVisible();
+  await page.setViewportSize({ width: 390, height: 844 });
+  await titledSource.click();
+  await expect(page.getByRole("dialog")).toContainText(
+    "Inspect the seal before operation.",
+  );
+  await expect(page.getByRole("dialog")).toHaveCSS("opacity", "1");
+  await page.screenshot({
+    path: testInfo.outputPath("knowledge-citation-mobile.png"),
+    fullPage: true,
+  });
+});
diff --git a/frontend/tests/unit/components/workspace/citations/knowledge-source.dom.test.tsx b/frontend/tests/unit/components/workspace/citations/knowledge-source.dom.test.tsx
new file mode 100644
index 000000000..8cf0ca3be
--- /dev/null
+++ b/frontend/tests/unit/components/workspace/citations/knowledge-source.dom.test.tsx
@@ -0,0 +1,130 @@
+import type { Message } from "@langchain/langgraph-sdk";
+import { afterEach, describe, expect, it } from "@rstest/core";
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+
+import { ArtifactLink } from "@/components/workspace/citations/artifact-link";
+import {
+  KnowledgeCitationLink,
+  KnowledgeSourcesPanel,
+  KnowledgeSourcesProvider,
+} from "@/components/workspace/citations/knowledge-source";
+import { createMarkdownLinkComponent } from "@/components/workspace/messages/markdown-link";
+import { I18nProvider } from "@/core/i18n/context";
+
+const id = "0123456789abcdef0123456789abcdef-1";
+const href = `#knowledge-${id}`;
+const messages = [
+  {
+    type: "tool",
+    name: "knowledge_search",
+    content: "retrieved",
+    tool_call_id: "call",
+    artifact: {
+      knowledge_sources: {
+        version: 1,
+        sources: [
+          {
+            id,
+            provider: "ragflow",
+            document_name: "Manual.pdf",
+            dataset_name: "Engineering",
+            text: "The limit is 42.\n<script>invalid</script>",
+            truncated: false,
+            pages: [3],
+          },
+        ],
+      },
+    },
+  },
+] as unknown as Message[];
+afterEach(cleanup);
+
+function App({ items = messages }: { items?: Message[] }) {
+  return (
+    <I18nProvider initialLocale="en-US">
+      <KnowledgeSourcesProvider messages={items}>
+        <KnowledgeCitationLink href={href}>1</KnowledgeCitationLink>
+        <KnowledgeSourcesPanel content={`Limit: 42. [citation:1](${href})`} />
+      </KnowledgeSourcesProvider>
+    </I18nProvider>
+  );
+}
+
+describe("knowledge source dialogs", () => {
+  it("opens the actual excerpt and source page from both citation and source list", () => {
+    render(<App />);
+    const buttons = screen.getAllByRole("button", {
+      name: "View source: Manual.pdf",
+    });
+    expect(buttons.length).toBe(2);
+    fireEvent.click(buttons[0]!);
+    const dialog = screen.getByRole("dialog");
+    expect(dialog.textContent).toContain("Pages 3");
+    expect(dialog.textContent).toContain("The limit is 42.");
+    expect(dialog.querySelector("script")).toBeNull();
+  });
+  it("restores citations from persisted JSON and loses access on conversation switch", () => {
+    const view = render(
+      <App items={JSON.parse(JSON.stringify(messages)) as Message[]} />,
+    );
+    expect(
+      screen.getAllByRole("button", { name: "View source: Manual.pdf" }).length,
+    ).toBe(2);
+    view.rerender(<App items={[]} />);
+    expect(
+      screen.queryByRole("button", { name: "View source: Manual.pdf" }),
+    ).toBeNull();
+    expect(
+      screen.getByTitle(
+        "Source evidence is unavailable in the loaded conversation.",
+      ),
+    ).toBeDefined();
+  });
+});
+
+for (const [surface, Link] of [
+  ["message", createMarkdownLinkComponent()],
+  ["artifact", ArtifactLink],
+] as const) {
+  describe(`${surface} knowledge destinations`, () => {
+    for (const label of ["Manual.pdf", "citation:1"]) {
+      for (const destination of [href, href.replace("#", "#user-content-")]) {
+        it(`opens ${label} at ${destination}`, () => {
+          render(
+            <I18nProvider initialLocale="en-US">
+              <KnowledgeSourcesProvider messages={messages}>
+                <Link href={destination}>{label}</Link>
+              </KnowledgeSourcesProvider>
+            </I18nProvider>,
+          );
+          fireEvent.click(
+            screen.getByRole("button", { name: "View source: Manual.pdf" }),
+          );
+          expect(screen.getByRole("dialog").textContent).toContain(
+            "The limit is 42.",
+          );
+        });
+      }
+    }
+    it("keeps missing sources unavailable and external links navigable", () => {
+      render(
+        <I18nProvider initialLocale="en-US">
+          <KnowledgeSourcesProvider messages={[]}>
+            <Link href={href}>Manual.pdf</Link>
+            <Link href="https://example.com/manual">External manual</Link>
+          </KnowledgeSourcesProvider>
+        </I18nProvider>,
+      );
+      expect(
+        screen.getByTitle(
+          "Source evidence is unavailable in the loaded conversation.",
+        ),
+      ).toBeDefined();
+      expect(
+        screen
+          .getByRole("link", { name: "External manual" })
+          .getAttribute("href"),
+      ).toBe("https://example.com/manual");
+    });
+  });
+}
diff --git a/frontend/tests/unit/core/knowledge/sources.test.ts b/frontend/tests/unit/core/knowledge/sources.test.ts
new file mode 100644
index 000000000..359411012
--- /dev/null
+++ b/frontend/tests/unit/core/knowledge/sources.test.ts
@@ -0,0 +1,100 @@
+import type { Message } from "@langchain/langgraph-sdk";
+import { describe, expect, it } from "@rstest/core";
+
+import {
+  citedKnowledgeSources,
+  collectKnowledgeSources,
+  knowledgeSourceId,
+} from "@/core/knowledge/sources";
+
+const id = "0123456789abcdef0123456789abcdef-1";
+const source = {
+  id,
+  provider: "ragflow",
+  document_name: "Manual.pdf",
+  dataset_name: "Engineering",
+  text: "Limit: 42.",
+  truncated: false,
+  pages: [3],
+};
+const message = {
+  type: "tool",
+  name: "knowledge_search",
+  content: "retrieved",
+  tool_call_id: "call",
+  artifact: { knowledge_sources: { version: 1, sources: [source] } },
+} as unknown as Message;
+
+describe("knowledge citation provenance", () => {
+  it("resolves repeated citations to the persisted tool evidence after JSON reload", () => {
+    const messages = JSON.parse(JSON.stringify([message])) as Message[];
+    const sources = collectKnowledgeSources(messages);
+    const citation = `[citation:1](#knowledge-${id})`;
+    expect(citedKnowledgeSources(`${citation} ${citation}`, sources)).toEqual([
+      source,
+    ]);
+    expect(knowledgeSourceId(`#knowledge-${id}`)).toBe(id);
+    expect(knowledgeSourceId(`#user-content-knowledge-${id}`)).toBe(id);
+  });
+  it("does not let model labels or human artifacts invent a source", () => {
+    const sources = collectKnowledgeSources([
+      { ...message, type: "human" } as Message,
+      { ...message, type: "ai" } as Message,
+    ]);
+    expect(sources.size).toBe(0);
+    expect(
+      citedKnowledgeSources(`[citation:invented](#knowledge-${id})`, sources),
+    ).toEqual([]);
+    expect(knowledgeSourceId(`https://evil.test/#knowledge-${id}`)).toBeNull();
+  });
+  it("ignores citations in code and images", () => {
+    const link = `[citation:1](#knowledge-${id})`;
+    expect(
+      citedKnowledgeSources(
+        `\`${link}\`\n\n\`\`\`\n${link}\n\`\`\`\n!${link}`,
+        collectKnowledgeSources([message]),
+      ),
+    ).toEqual([]);
+  });
+  it("rejects malformed and unknown artifact versions", () => {
+    for (const payload of [
+      { version: 2, sources: [source] },
+      { version: 1, sources: [{ ...source, pages: [-1] }] },
+      { version: 1, sources: [{ ...source, text: 42 }] },
+    ]) {
+      const bad = {
+        ...message,
+        artifact: { knowledge_sources: payload },
+      } as Message;
+      expect(collectKnowledgeSources([bad]).size).toBe(0);
+    }
+  });
+  it("keeps independent source identities for repeated searches", () => {
+    const other = {
+      ...source,
+      id: "fedcba9876543210fedcba9876543210-1",
+      text: "Limit: 43.",
+    };
+    const next = {
+      ...message,
+      artifact: { knowledge_sources: { version: 1, sources: [other] } },
+    } as Message;
+    expect(collectKnowledgeSources([message, next, message]).size).toBe(2);
+  });
+});
+
+it("collects ordinary Sources-section links without collecting code or images", () => {
+  const link = `[Manual.pdf](#knowledge-${id})`;
+  expect(
+    citedKnowledgeSources(
+      `## Sources\n- ${link}\n${link}`,
+      collectKnowledgeSources([message]),
+    ),
+  ).toEqual([source]);
+  expect(
+    citedKnowledgeSources(
+      `\`${link}\`\n!${link}`,
+      collectKnowledgeSources([message]),
+    ),
+  ).toEqual([]);
+});