fix(mcp): stop reporting sandbox execute failures to Sentry

[kentcdodds]

Summary

Sentry issue KODY-CLOUDFLARE-1N is a warning with tags mcp.sandbox_error=true / mcp.tool=execute: an MCP execute caller/module threw the non-Error string b[t]?.title?.map is not a function (minified user/package code). That is not a platform defect.

The same root cause class already has a draft sibling PR (#915 / KODY-CLOUDFLARE-1H). This PR lands the filter so sandbox failures stay on structured mcp-event logs and no longer open Sentry warning issues that trip triage automation. Platform MCP failures still report at error level.

Sibling sandbox-noise issues sharing mcp.sandbox_error:true (e.g. missing secrets, bad Notion paths, invokeChecked param errors) are addressed by the same change.

Test plan

• observability.node.test.ts asserts sandbox failures still emit mcp-event but do not call captureMessage / captureException, using the 1N error signature
• Non-sandbox failures still report to Sentry
• Pre-push validate passed on push

System recap — extends existing primitives (medium risk)

Mode: recap · Base: main @ 49893e20 · Head: 37ae7f38

Classification: extends — changes MCP failure reporting so sandbox/user-module errors stay on logs only and no longer open Sentry issues.

Primitives touched

Primitive	Group	Impact
mcp-server	surfaces	extends — sandbox execute failures no longer reported to Sentry

System map

Sandbox execute failures used to become Sentry warnings via MCP observability; they now stay on the mcp-event log path only.

Legend: green = composes (wiring only) · amber = extended by this PR · red = new primitive · gray = context.

flowchart LR
	mcpExecute["mcp execute<br/>sandbox run"]:::untouched
	mcpEvent["mcp-event log"]:::untouched
	observability["mcp-server<br/>observability"]:::extended
	sentry["Sentry"]:::untouched
	mcpExecute -->|"result.error"| observability
	observability -->|"always"| mcpEvent
	observability -->|"platform failures only"| sentry
	classDef touched fill:#1a7f37,color:#fff
	classDef extended fill:#9a6700,color:#fff
	classDef added fill:#cf222e,color:#fff
	classDef untouched fill:#57606a,color:#fff

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Before / after

Before: execute sandbox failures (sandboxError: true) were captured in Sentry as warnings (Unknown: …), including thrown strings from caller modules such as b[t]?.title?.map is not a function.

After: sandbox failures remain on mcp-event logs; only non-sandbox MCP failures are sent to Sentry at error level.

Risk and invariants

• Medium: changes production error visibility for one failure class; does not touch auth, storage isolation, or capability contracts.
• Per-user isolation unchanged; Sentry user id attachment for platform MCP failures is unchanged.

Docs

No doc updates; behavior is an observability policy change covered by unit tests.

  

Summary by CodeRabbit

• Bug Fixes
  • Prevented sandbox-related MCP failures from being reported to Sentry.
  • Ensured genuine platform errors are captured with error-level severity and the associated user context.
  • Preserved sandbox failure details in application logs for troubleshooting.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 02c59990-44fc-49aa-ae3c-40bbed9034c8

📥 Commits

Reviewing files that changed from the base of the PR and between 32d97b7 and 37ae7f3.

📒 Files selected for processing (2)

• packages/worker/src/mcp/observability.node.test.ts
• packages/worker/src/mcp/observability.ts

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📝 Walkthrough

Walkthrough

MCP sandbox failures now remain in event logs without Sentry reporting. Non-sandbox failures continue through Sentry exception capture with error-level scope configuration, and tests cover both routing paths.

Changes

MCP observability

Layer / File(s)	Summary
Failure reporting and validation packages/worker/src/mcp/observability.ts, packages/worker/src/mcp/observability.node.test.ts	Sandbox failures return before Sentry interaction, while non-sandbox failures use an error-level scope and capture exceptions. Tests verify event logging, capture behavior, and user scope setup.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• kentcdodds/kody#720: Adds console spying infrastructure used by the observability test’s console.info assertions.
• kentcdodds/kody#917: Makes the corresponding sandbox failure and Sentry reporting changes in the same observability area.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: sandbox MCP failures are no longer reported to Sentry.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch cursor/sentry-triage-kody-cloudflare-1n-dc45

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[github-actions]

🔎 Preview deployed: https://kody-pr-918.kody-a99.workers.dev

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