4 Commits

Author SHA1 Message Date
Xinmin Zeng
09988caf95
feat(skills): request-scoped secrets for skills (closes #3861) (#3871)
* feat(sandbox): per-call env injection + platform-secret scrubbing for skills

Add an env parameter to Sandbox.execute_command (abstract + local + AIO) so request-scoped secrets can be injected into skill subprocesses, and scrub platform credentials (*KEY*/*SECRET*/*TOKEN*/*PASSWORD*/*CREDENTIAL*) from the inherited environment by default so scoped injection is not security theatre. LocalSandbox always passes an explicit scrubbed env; AioSandbox routes env-bearing commands through bash.exec(env=) on a fresh session and leaves the legacy persistent-shell path unchanged. Part of #3861. BEHAVIOR CHANGE: execute_command no longer inherits the full os.environ; Windows encoding tests updated to assert the scrubbed dict.

* feat(skills): parse required-secrets frontmatter declaration

Add SecretRequirement and Skill.required_secrets, and parse the required-secrets SKILL.md frontmatter field (a string list or {name, optional} mappings), dropping malformed entries with a warning so one bad declaration does not invalidate the skill. The declared name is both the context.secrets key and the env var injected at activation. Part of #3861.

* feat(runtime): request-scoped secret carrier (context.secrets)

Add SECRETS_CONTEXT_KEY + extract_request_secrets, centralising the context.secrets carrier contract. The existing context passthrough (build_run_config -> _build_runtime_context) already carries the sub-key to runtime.context without mirroring it into configurable; characterization tests lock that behaviour. Part of #3861.

* feat(skills): inject declared secrets at slash-activation into bash env

Binding point A: when a skill is slash-activated, SkillActivationMiddleware resolves its declared required-secrets against the request's context.secrets and writes the per-run injection set to runtime.context. The bash tool forwards that set to execute_command(env=). A skill cannot harvest a host platform credential (is_host_platform_secret guard, cf. GHSA-rhgp-j443-p4rf), and injected values are redacted from bash output (mask_secret_values) so an echoed secret never re-enters the prompt/trace. Part of #3861.

* test(skills): lock the five secret leak surfaces + add trace redaction helper

Regression tests assert the secret value is absent from all five surfaces: prompt (activation message), checkpoint (graph state vs context separation), audit (journal records names only), trace (metadata builder never copies context; never mirrored to configurable), and stdout (mask_secret_values). Add redact_secret_context_keys as a defensive helper for any context serialization. Part of #3861.

* docs(backend): document request-scoped secrets for skills

Add Request-Scoped Secrets subsection (Skills) + env policy note (Sandbox) and the execute_command(env=) signature change, per the doc-sync policy. Part of #3861.

* fix(skills): close gaps found by end-to-end verification of request-scoped secrets

Real-gateway e2e + independent review of #3861 surfaced three defects, now fixed:

1. Slash activation never fired in the live chain. InputSanitizationMiddleware
   wraps user input in BEGIN/END markers before SkillActivationMiddleware sees it,
   and the original text was only preserved when an upload or IM channel set it.
   For a plain text message the slash command became undetectable, so no secret
   was ever resolved. Fix: the sanitizer now setdefaults the pre-wrap text into
   ORIGINAL_USER_CONTENT_KEY (additive; sanitization behaviour unchanged), so
   slash activation works for all messages. Pre-existing latent bug surfaced here.

2. The raw request config (with context.secrets) was persisted to runs.kwargs_json
   and echoed by the run API (RunResponse.kwargs). Fix: redact_config_secrets()
   strips secret-bearing context keys from the persisted/echoed copy in start_run;
   the live config that drives the run keeps them. build_run_config now also sets
   configurable.thread_id on the context path (the checkpointer requires it).

3. Connection-string credentials (DATABASE_URL, REDIS_URL, SENTRY_DSN, GH_PAT, ...)
   were not scrubbed from the inherited sandbox env. Fix: env_policy adds a *DSN*
   pattern plus an explicit connection-string denylist (no blanket *URL* — benign
   service URLs stay readable).

Verified end-to-end via a real gateway run (real LLM + skill activation + bash):
the secret reaches the sandbox subprocess and appears in NONE of prompt, trace,
checkpoint, audit, stdout, runs.kwargs_json, or the run API. Part of #3861.

* docs(backend): document the env scrub, persistence redaction, and sanitizer interaction

Sync the Request-Scoped Secrets section with the verification-driven fixes: inherited-env scrub (incl. connection-string denylist), run-record/run-API redaction as the 6th sealed leak surface, and the sanitizer preserving original content so slash activation fires. Part of #3861.

* fix(skills): inject caller secret over scrubbed host value; drop redundant host-name guard

A real-world demo (a skill calling a third-party cloud API with a request-scoped
key) exposed that the is_host_platform_secret guard was both wrong and harmful:
it refused to inject a caller-supplied secret whenever a same-named variable
existed in the Gateway env — which is exactly the #3861 use case (a per-user key
overriding a shared platform key). The guard was also redundant: build_sandbox_env
already scrubs secret-looking names from the inherited env before injection, so a
skill can never read a host credential — it only ever receives the caller's value.

Remove the guard; the injected (caller) value simply wins over the scrubbed host
value. Verified end-to-end: the agent called the real cloud API successfully with
the caller's key, the host's same-named key was scrubbed and never used, and the
caller's key leaked to none of the surfaces. Part of #3861.

* fix(skills): address review on request-scoped secrets (#3861)

Review fixes from PR #3871:

- E2BSandbox.execute_command now accepts env/timeout and routes them to
  commands.run(envs=, timeout=). The bash tool passes env= unconditionally,
  so the prior signature (command only) raised TypeError on every e2b bash
  call and broke e2b deployments entirely. env=None stays backward-compatible.
- SkillActivationMiddleware clears the active-secret set before resolving each
  activation, so a later skill in the same run never inherits an earlier
  skill's injection set (the #3861 contract: a skill only receives what the
  caller supplied AND that skill declared).
- AioSandbox env path uses a dedicated _DEFAULT_HARD_TIMEOUT — bash.exec exposes
  no idle/no-change timeout, so the prior reuse of the legacy idle constant
  conflated wall-clock vs idle semantics. The env path also retries on the
  ErrorObservation signature now, sharing the legacy persistent-shell recovery
  contract.
- mask_secret_values skips values below a minimum length floor so a short
  declared secret (e.g. "42") cannot shred unrelated bytes (exit codes,
  timestamps, sizes) of tool output. The secret is still injected into the
  subprocess; only the output mask skips it.

session_id reuse on the env path is intentionally NOT added: a shared session
could let request-scoped secrets ride the session env into later commands,
which the SDK does not contractually forbid. The fresh-session choice matches
the LocalSandbox model (each call is a fresh subprocess); the trade-off
(consecutive env-bearing calls do not share cwd/venv/exports) is documented on
_execute_with_env.
2026-07-03 07:51:22 +08:00
Zhipeng Zheng
e7b88a97ed
fix(security): add input sanitization middleware for prompt-injection defense (#3630) (#3662)
InputSanitizationMiddleware: escapes blocked XML tags in user messages (<system> -> &lt;system&gt;) — de-identify, don't reject (AWS PII-style). Wraps user input in plain-text boundary markers (--- BEGIN/END USER INPUT ---) per OWASP structured-prompt guidance. System-Context Confidentiality clause prevents LLM from revealing internal instructions. Boundary-marker layer hardened against delimiter injection (self-suppression + break-out). Multimodal content blocks preserved during sanitization.

Addresses review feedback from @fancyboi999 and @WillemJiang:

1. Boundary-marker injection: strict startswith+endswith idempotency, neutralize user-supplied BEGIN/END tokens, forged-idempotency bypass fixed

2. Multimodal data loss: _rebuild_content preserves interleaved non-text blocks

3. CI fixes: replay_provider strips boundary markers before hashing, middleware chain assertions updated

4. Lint: ruff format applied on Linux (slice spacing + f-string collapse)

Test: 71 input_sanitization + 1 replay_golden + 14 tool_error + 93 tool_output_budget = 179/179 passed
2026-06-21 19:01:43 +08:00
Huixin615
64d923b0fd
fix(middleware): externalize oversized tool output into sandbox for non-mounted sandboxes (#3417)
* fix(middleware): externalize oversized tool output into sandbox for non-mounted sandboxes

ToolOutputBudgetMiddleware persisted oversized tool results to the host
filesystem and returned a /mnt/user-data/outputs virtual path. For sandboxes
that do not use thread-data mounts (e.g. remote AIO sandbox), that virtual
path does not exist inside the sandbox, so the model's read_file tool could
not read it back and reported 'file not found'.

Branch on SandboxProvider.uses_thread_data_mounts:

- Mounted sandboxes (local Docker, AIO + LocalContainerBackend) keep the
  original host-disk path; the host outputs dir is bind-mounted to the same
  virtual path inside the sandbox, so behavior is unchanged.

- Non-mounted (remote) sandboxes externalize into the sandbox itself via
  execute_command('mkdir -p ...') + write_file + 'test -s' validation. The
  validation step is required because AIO sandbox execute_command returns
  'Error: ...' as a string on failure instead of raising, so a silent mkdir
  failure would otherwise leak through.

Any failure (rejected subdir, mkdir/write/validate error) falls back to the
existing inline head+tail truncation, so an unreadable path is never returned
to the model.

The sandbox resolver reads the sandbox_id that SandboxMiddleware already
writes into runtime.state['sandbox']; it never calls provider.acquire(),
keeping the tool-call hot path free of blocking I/O. Tools that do not use a
sandbox (web_search, MCP, ...) resolve to None and fall through to inline
truncation, which is the safe behavior for them.

Fixes #3416

* fix(middleware): address Copilot review feedback on sandbox externalization

- Make get_sandbox_provider() lookup best-effort in _budget_content: only
  query when outputs_path or sandbox is available, and fall back to inline
  truncation if provider initialization raises rather than propagating
  the error. A resolved sandbox instance is sufficient on its own to take
  the non-mounted externalization branch.
- Strict-match the sandbox post-write validation echo
  (check.strip() == 'OK') to avoid false positives if execute_command
  ever surfaces unrelated stdout/stderr containing 'OK' as a substring.

Refs: #3417

* test: fix flaky tests relying on /nonexistent/... path under container root

Two tests in this module (test_returns_none_on_invalid_path and
test_fallback_when_disk_write_fails) used paths like
'/nonexistent/impossible/path' to trigger _externalize's OSError
fallback. These paths are creatable when the test process runs as root
inside the CI container: os.makedirs(..., exist_ok=True) successfully
creates the entire chain under /, so the OSError branch is never hit
and the tests fail. Reproducible on main independently of this PR.

Switch to '/dev/null/cannot-mkdir-here'. /dev/null is a character
device on both Linux and macOS, so os.makedirs always fails with
NotADirectoryError regardless of privileges, reliably exercising the
OSError fallback.

* fix(tool-output-budget): only consult sandbox provider when a sandbox is resolved

The previous revision called get_sandbox_provider() whenever externalization
was triggered, including on the legacy host-disk path. Environments without
a configured sandbox -- in particular CI runners without a config.yaml --
would raise FileNotFoundError there, get caught, and silently fall back to
inline truncation. That defeated the host-disk externalization path that
predates this PR and was the root cause of the regressing legacy tests.

Restructure the branching so the provider is only consulted when a sandbox
has actually been resolved for the current tool call:

  - sandbox resolved + provider.uses_thread_data_mounts: host-disk write
    (bind-mounted into the sandbox, equivalent to a sandbox-side write).
  - sandbox resolved + non-mounted provider:             sandbox write (#3416).
  - no sandbox + outputs_path:                           host-disk write
    (legacy / non-sandbox tools, no provider call at all).
  - otherwise:                                           inline fallback.

No test changes; the legacy externalization tests are provider-agnostic by
construction and now pass without monkeypatching.

Refs: #3416

* test(tool-output-budget): assert legacy path does not call sandbox provider

Lock in the contract introduced by d6e2d25b: when no sandbox is resolved
for a tool call, _budget_content must externalize to the host outputs
directory without consulting get_sandbox_provider(). Regressing this would
re-break legacy / non-sandbox tools in environments without a configured
sandbox (e.g. CI without config.yaml), which is the failure mode #3416's
fix avoids.

The test injects a get_sandbox_provider that raises on call, so any
future refactor that moves the provider lookup out of the sandbox-only
branch will fail loudly.

Refs: #3416
2026-06-08 12:24:48 +08:00
Xinmin Zeng
ca487578a4
feat(agent): add ToolOutputBudgetMiddleware for oversized tool output protection (#3303)
* feat(agent): add ToolOutputBudgetMiddleware for oversized tool output protection

Closes #3289. Adds a unified middleware that enforces per-result budgets
on ALL tool outputs (MCP, sandbox, community, custom), preventing
oversized external tool results from blowing the model context window.

Design informed by claude-code (persistToolResult), hermes-agent
(tool_result_storage), and pi (OutputAccumulator) — the three most
mature implementations in production coding-agent frameworks.

Key features:
- Disk externalization: oversized outputs written to thread-local
  .tool-results/ directory, replaced with compact preview + file
  reference. Model can read full output via read_file with offset/limit.
- Fallback truncation: head+tail truncation when disk is unavailable
  (no thread_data, write failure), ensuring the context is always
  protected.
- read_file exemption: prevents persist-read-persist infinite loops
  (independently discovered by claude-code, hermes-agent, and pi).
- Per-tool threshold overrides via config.
- Line-boundary-aware truncation (no partial lines in previews).
- Multimodal content passthrough (images/structured blocks skip budget).
- Historical ToolMessage patching in wrap_model_call for checkpoint
  recovery scenarios.

Related: #3222 (design RFC), #1844 (comprehensive context management),
#3137 (write_file args compaction), #1677 (sandbox tool truncation).

* test: add MCP content_and_artifact format coverage

Add 5 tests for MCP tool output format (list of content blocks):
- text content blocks are extracted and budgeted
- multiple text blocks are joined and budgeted
- image content blocks are skipped (multimodal passthrough)
- mixed text+image blocks are skipped
- small text blocks pass through unchanged

Total test count: 59 (was 54).

* fix(agent): address Codex review findings for ToolOutputBudgetMiddleware

Three issues identified by Codex code review, all fixed:

1. `enabled` config field was unused — middleware now checks
   `config.enabled` and skips all processing when disabled.

2. `_build_fallback` could exceed `fallback_max_chars` — the marker
   text itself (~139 chars) was not deducted from the budget. Now
   pre-computes marker overhead and falls back to hard slice when
   max_chars is smaller than the marker.

3. Sync file I/O in async path — `awrap_tool_call` now delegates
   `_patch_result` to `asyncio.to_thread` to avoid blocking the
   event loop during disk writes.

Tests updated to use realistic fallback_max_chars values (500+)
that can accommodate the marker overhead, plus two new tests:
- `test_result_never_exceeds_max_chars` (parametric across sizes)
- `test_very_small_max_chars_does_not_crash`

* fix(agent): address Copilot review — path traversal, async perf, shared config

1. Path traversal defense: sanitize tool_name via _sanitize_tool_name()
   (strips separators, .., absolute paths), validate storage_subdir is
   relative, and verify resolved filepath stays inside storage_dir.

2. Async hot-path optimization: add _needs_budget() cheap check before
   asyncio.to_thread offload — small outputs (99% of calls) skip the
   thread overhead entirely.

3. Replace shared module-level _DEFAULT_CONFIG with _default_config()
   factory to prevent cross-instance mutation of mutable fields.

12 new tests: TestSanitizeToolName (5), TestExternalizePathTraversal (3),
TestNeedsBudget (4).

* fix(agent): correct preview hint to match read_file actual API

read_file uses start_line/end_line (1-indexed line numbers), not
offset/limit. The previous wording was copied from hermes-agent
which has a different read_file interface.

* perf(agent): hoist hot-path imports, add model-call pre-scan (review #3303)

Address maintainer review feedback:

1. Hoist inline imports to module level — `import asyncio` (was in
   awrap_tool_call hot path) and `from dataclasses import replace`
   (was in _patch_result) now live at module top.

2. Add a cheap pre-scan to _patch_model_messages so the historical
   message list is not rebuilt on every model call when nothing is
   oversized (the common case once results are budgeted at tool-call
   time). Also adds the same _needs_budget gate to the sync
   wrap_tool_call for symmetry with awrap_tool_call.

The pre-scan is refactored into per-tool-aware helpers
(_effective_trigger / _tool_message_over_budget) that mirror the exact
trigger conditions in _budget_content — including tool_overrides — so
the fast-path can never produce a false negative (silently skipping
budgeting for a tool with a low per-tool threshold).

7 new regression tests lock the per-tool-override-through-pre-scan path
and the model-call early return.

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-05-29 22:59:26 +08:00