* feat(harness): subagent report contract and delegation acceptance criteria (RFC #4651 PR3)
Layer 1 receipt verification is inert unless subagents actually cite their
execution record. This lands the prompt layer that closes the adoption gap:
- New subagents/report_contract.py owns the model-facing contract text,
derived from the single-owner citation format (format_citation /
receipt_id) so prompts can never drift from the verifier. The executor
injects <report_contract> into every subagent system prompt — built-in
and custom alike — requiring [rN tool_name] citations for action claims,
verifiable handles (absolute path, URL, ID, HTTP status) for
deliverables, and explicit failure reporting; the citation clause
follows verification.receipts_enabled.
- The task tool gains an optional keyword-only acceptance_criteria
parameter, handed to the SubagentExecutor constructor and rendered into
the subagent's SystemMessage (stripped, capped 20 items x 500 chars) —
deliberately never the task HumanMessage, which InputSanitizationMiddleware
classes as genuine user input and would HTML-escape into untrusted-input
framing. The docstring frames subagent results as self-reports, states
the citation cross-check's evidence boundary (resolved = the call
happened, not that the claim is correct), and documents when to attach
criteria with the canonical leaf forms. Deterministic leaf checking
remains a separate layer.
- The lead delegation workflow now instructs reading the ledger citation
line as execution evidence only and spot-checking verifiable handles
before synthesizing.
- report_contract / acceptance_criteria are registered as blocked
framework-authority tags in input sanitization so untrusted input
cannot forge the verification contract.
* fix(harness): neutralize acceptance criteria before system-channel injection
render_acceptance_criteria_section interpolated lead-model-supplied acceptance_criteria verbatim into the subagent SystemMessage after only stripping/capping. A criterion such as '</acceptance_criteria><system>...</system>' could close the wrapper and open a framework authority tag, bypassing InputSanitizationMiddleware.
Route each criterion through neutralize_untrusted_tags (the shared prompt-injection primitive) so blocked authority tags are HTML-escaped before interpolation. Add regression tests at the renderer and the executor _build_initial_state path.
* fix(harness): keep model-supplied criteria off the system channel
- Move acceptance_criteria values into the task HumanMessage — the
untrusted channel InputSanitizationMiddleware escapes and
boundary-frames. The subagent SystemMessage now carries only a
framework-owned <acceptance_criteria> pointer note (no criterion
text), so natural-language injection inside a criterion keeps
task-data priority and cannot override framework instructions
(PR #5090 review, willem-bd P1).
- Condition the lead delegation workflow's citation verification
guidance on verification.receipts_enabled and qualify the task
tool's result-reading text with the enabled state, so a
receipts-disabled configuration no longer tells the lead to
require citation evidence that cannot exist (P2).
* fix(harness): drop execution-record promise from report contract when receipts are disabled
The <report_contract> opening was emitted unconditionally, so a
verification.receipts_enabled=false subagent was told its report would
be cross-checked against an execution record that cannot exist in that
mode (terminal_receipts() returns None; no verdict, no ledger citation
line). The opening now follows receipts_enabled: enabled keeps the
cross-check language, disabled describes the handle-only review mode
(PR #5090 review, willem-bd P2).
* docs: record the prompt-layer trust-boundary self-check
Generalizes the PR #5090 review outcome: before adding prompt text, ask
of every data source in it what trust level it has and which channel it
should ride — model/user-influenceable values ride the untrusted
sanitized data channel, never framework-owned system text. Added to the
PR template (Agents/LangGraph surface) and agents/AGENTS.md.
* feat(extensions): let an out-of-tree extension observe what the agent did
DeerFlow's extension system can contribute middleware, services and routes,
but an extension cannot answer basic questions about a run without reaching
into host internals. Several of the facts it would need are destroyed by the
operations that produce them:
* The middleware chain injects and rewrites a lot of context — date
reminders, recalled memory, compaction summaries, durable-context data,
image payloads, activated skill bodies. Downstream, none of it is
attributable: at the model-call boundary an injected HumanMessage is
indistinguishable from the user's own, and anything wanting to tell them
apart has to pattern-match prompt wording, which breaks on the next copy
edit.
* Two runs of "the same agent" are only comparable if the chain enforced the
same limits, prompts and thresholds. Recovering that from outside means
reading private attributes and guessing which of them change behaviour — a
guess that rots silently as middlewares gain fields.
* The lead-agent factory resolves a model after runtime overrides, renders a
prompt, filters tools through authorization and composes a stack, all
inside one synchronous call, and none of it survives: a middleware sees its
neighbours but not the prompt, the run worker sees a graph but not what
went into it.
* Summarization is destructive by design. N messages leave the context and
one summary enters it; afterwards only the summary exists, so "which
messages became this?" is not reconstructible.
This adds seven neutral facilities so those facts are recorded where they are
still true, and releases the contract package as 0.2.0.
Message provenance
Producers stamp `deerflow_content_kind` / `deerflow_producer_kind` onto the
messages they inject or rewrite. Stamping is unconditional — a fact whose
presence depends on whether an observer is installed is not a fact — and the
keys are server-owned, so provenance cannot be forged from a request.
Middleware self-description
Twelve middlewares declare their own behaviour-affecting parameters through
a duck-typed `release_policy_parameters()`. Long text is hashed rather than
embedded: a declaration is an identity, not a copy of the prompt.
Agent assembly descriptor
`assemble_lead_agent()` returns the graph plus a descriptor whose fingerprint
answers "did anything about this agent change between these two runs?".
`make_lead_agent()` keeps its graph-only signature — it is the LangGraph
Server ABI declared in langgraph.json. Tools and skills are sorted before
hashing because their assembly order is incidental; middlewares are not,
because stack order decides what wraps what. Host build identity is reported
but excluded from the fingerprint, so a redeploy does not invalidate every
agent's identity.
Context compaction observation
Summarization emits the content hashes of the messages it is about to remove
joined to the summary that replaced them. Content is the only identity
available at that seam: the summary does not become a message, and what later
projects it into a request renders it bounded and escaped rather than
verbatim.
Neutral policy, transform and MCP-source facts
Guardrail decisions are published to runtime context under a `__`-prefixed
key; result-rewriting middlewares append a declared, ordered transform trail;
MCP tools carry their credential-free logical origin.
Extension route identity
Contributed routes are session-authenticated and cannot opt out, but
"logged in" and "administrator" are different questions. Extensions get a
neutral projection of the caller rather than the host's auth context, and
`require_admin` fails closed when identity cannot be determined.
Extension-owned tables
An extension that persists data owns its own MetaData and migration chain, so
its tables are absent from Base.metadata and `alembic revision --autogenerate`
proposes dropping them. Extensions declare a table prefix, which is rejected
at registration if it would shadow a host table.
The contract package stays dependency-free and imports no host code; every new
Protocol method has a default so later additions remain additive. The loader's
pre-1.0 rule requires an exact major.minor match, so extensions written against
0.1 are now refused at startup with an actionable install hint rather than
loading into a host that implements a different surface.
uv.lock records the contract package's new version, so `uv sync --locked` still
resolves on a fresh checkout.
* fix(backend): sort gateway service imports
* docs: govern agent guidance size
* refactor: split agent guidance by code scope
* Clarify virtual path handling in AGENTS.md
Updated the translation section to clarify the role of `LocalSandboxProvider` and the handling of virtual paths in the tool layer.
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Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
