fix(server): reject over-deep JSON request bodies before parsing

[seonghobae]

Summary

• Strix (running on PR fix(api): casefold message roles and tool/function types over HTTP #716's changed-file scope) reported a MEDIUM finding: _coerce_json parses request bodies with json.loads with no nesting-depth cap, so a deeply nested payload well under max_body_bytes can still burn disproportionate CPU/stack during parsing (JSON bomb DoS).
• Add _reject_excessive_json_nesting: a cheap, stdlib-only byte scan (skips over string contents correctly) that rejects nesting past MAX_JSON_NESTING_DEPTH (32) before json.loads ever runs.
• fuzz/targets.py::exercise_request_body already treated RecursionError as an expected/benign outcome of deep nesting; this fix removes that failure mode entirely by rejecting it earlier with a proper RequestError.

Test plan

• python tests/test_request_body_json_depth.py
• python -m pytest tests/test_request_body_json_depth.py -q
• python -m pytest tests/fuzz -q
• python -m pytest tests -q --ignore=tests/fuzz (296 passed)
• CI product gates (Full unit + Semgrep, Strix re-scan)

[coderabbitai]

Warning

Review limit reached

@seonghobae, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 3 minutes

Limit details: You’ve used the included review currently available.

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits within each organization.

For paid Pro and Pro+ reviews, CodeRabbit uses a developer's included PR review attempts over the past 7 days to set the current hourly allowance. At typical activity levels, the full plan allowance applies. Higher sustained activity can lower the allowance until earlier attempts leave the 7-day window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 97ce65be-0d66-411c-a7a6-000704bfb3f6

📥 Commits

Reviewing files that changed from the base of the PR and between be40de0 and a842c4d.

📒 Files selected for processing (2)

• contextual_orchestrator/server.py
• tests/test_request_body_json_depth.py

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[opencode-agent]

Pull request overview

OpenCode cannot approve yet because required coverage evidence did not pass.

Review outcome

1. HIGH .github/workflows/opencode-review.yml:1 - Coverage evidence did not prove required test/docstring evidence

• Problem: The required coverage-evidence job result was failure, so OpenCode cannot establish approval sufficiency for this head.

• Root cause: Automated approval is only valid when the same-head coverage-evidence job proves supported repository test suites passed and configured docstring gates passed or were advisory, or reports not applicable because no supported source files or package manifests exist. Missing, failed, skipped, unavailable, or unsupported-tooling test evidence is a blocker.

• Fix: Install or configure the repository test/docstring evidence tooling when source files or package manifests exist, rerun the current-head coverage-evidence job, and approve only after it reports success with required evidence or explicit no-source not-applicable evidence.

• Regression test: Keep the approval branch checking needs.coverage-evidence.result == success before posting APPROVE, and publish REQUEST_CHANGES when coverage-evidence blocker states such as cancelled, skipped, failed, unsupported-tooling, or below-100 evidence are present.

• Result: REQUEST_CHANGES

• Reason: coverage-evidence result was failure, so required test/docstring evidence was not proven for current head f2b993bfddbfd5cb82bf251065709dba596f90a6.

• Head SHA: f2b993bfddbfd5cb82bf251065709dba596f90a6

• Workflow run: 32189622069

• Workflow attempt: 1

Coverage evidence

Coverage evidence job did not run or did not publish coverage evidence.

Changed-File Evidence Map

flowchart LR
  PR["PR changed files"] --> Evidence["OpenCode bounded evidence"]
  Evidence --> S1["Changed file: server.py"]
  S1 --> I1["repository behavior"]
  I1 --> R1["Review risk: Changed file: server.py"]
  R1 --> V1["required checks"]
  Evidence --> S2["Test: test_request_body_json_depth.py"]
  S2 --> I2["regression suite"]
  I2 --> R2["Review risk: Test: test_request_body_json_depth.py"]
  R2 --> V2["targeted test run"]

Loading

[opencode-agent]

OpenCode Review Overview

• Head SHA: f2b993bfddbfd5cb82bf251065709dba596f90a6
• Workflow run: 32194255112
• Workflow attempt: 1
• Gate result: REQUEST_CHANGES (approval step)

Pull request overview

OpenCode cannot approve yet because required coverage evidence did not pass.

Review outcome

1. HIGH .github/workflows/opencode-review.yml:1 - Coverage evidence did not prove required test/docstring evidence

• Problem: The required coverage-evidence job result was failure, so OpenCode cannot establish approval sufficiency for this head.

• Root cause: Automated approval is only valid when the same-head coverage-evidence job proves supported repository test suites passed and configured docstring gates passed or were advisory, or reports not applicable because no supported source files or package manifests exist. Missing, failed, skipped, unavailable, or unsupported-tooling test evidence is a blocker.

• Fix: Install or configure the repository test/docstring evidence tooling when source files or package manifests exist, rerun the current-head coverage-evidence job, and approve only after it reports success with required evidence or explicit no-source not-applicable evidence.

• Regression test: Keep the approval branch checking needs.coverage-evidence.result == success before posting APPROVE, and publish REQUEST_CHANGES when coverage-evidence blocker states such as cancelled, skipped, failed, unsupported-tooling, or below-100 evidence are present.

• Result: REQUEST_CHANGES

• Reason: coverage-evidence result was failure, so required test/docstring evidence was not proven for current head f2b993bfddbfd5cb82bf251065709dba596f90a6.

• Head SHA: f2b993bfddbfd5cb82bf251065709dba596f90a6

• Workflow run: 32194255112

• Workflow attempt: 1

Coverage evidence

Coverage evidence job did not run or did not publish coverage evidence.

Changed-File Evidence Map

flowchart LR
  PR["PR changed files"] --> Evidence["OpenCode bounded evidence"]
  Evidence --> S1["Changed file: server.py"]
  S1 --> I1["repository behavior"]
  I1 --> R1["Review risk: Changed file: server.py"]
  R1 --> V1["required checks"]
  Evidence --> S2["Test: test_request_body_json_depth.py"]
  S2 --> I2["regression suite"]
  I2 --> R2["Review risk: Test: test_request_body_json_depth.py"]
  R2 --> V2["targeted test run"]

Loading

[opencode-agent]

Pull request overview

OpenCode cannot approve yet because required coverage evidence did not pass.

Review outcome

1. HIGH .github/workflows/opencode-review.yml:1 - Coverage evidence did not prove required test/docstring evidence

• Problem: The required coverage-evidence job result was failure, so OpenCode cannot establish approval sufficiency for this head.

• Root cause: Automated approval is only valid when the same-head coverage-evidence job proves supported repository test suites passed and configured docstring gates passed or were advisory, or reports not applicable because no supported source files or package manifests exist. Missing, failed, skipped, unavailable, or unsupported-tooling test evidence is a blocker.

• Fix: Install or configure the repository test/docstring evidence tooling when source files or package manifests exist, rerun the current-head coverage-evidence job, and approve only after it reports success with required evidence or explicit no-source not-applicable evidence.

• Regression test: Keep the approval branch checking needs.coverage-evidence.result == success before posting APPROVE, and publish REQUEST_CHANGES when coverage-evidence blocker states such as cancelled, skipped, failed, unsupported-tooling, or below-100 evidence are present.

• Result: REQUEST_CHANGES

• Reason: coverage-evidence result was failure, so required test/docstring evidence was not proven for current head f2b993bfddbfd5cb82bf251065709dba596f90a6.

• Head SHA: f2b993bfddbfd5cb82bf251065709dba596f90a6

• Workflow run: 32194255112

• Workflow attempt: 1

Coverage evidence

Coverage evidence job did not run or did not publish coverage evidence.

Changed-File Evidence Map

flowchart LR
  PR["PR changed files"] --> Evidence["OpenCode bounded evidence"]
  Evidence --> S1["Changed file: server.py"]
  S1 --> I1["repository behavior"]
  I1 --> R1["Review risk: Changed file: server.py"]
  R1 --> V1["required checks"]
  Evidence --> S2["Test: test_request_body_json_depth.py"]
  S2 --> I2["regression suite"]
  I2 --> R2["Review risk: Test: test_request_body_json_depth.py"]
  R2 --> V2["targeted test run"]

Loading

Dismissing: mechanical 'coverage-evidence result was failure' rejection (root cause: atheris==3.0.0 has no Python 3.14 wheel, breaking the central coverage-sandbox build for every PR org-wide regardless of diff; real fix in #752, merging shortly). Not a content objection to this PR.