Repository navigation
fix(hooks): budget session-start to the 10,000-char hook cap, keep the trailer - #291
Merged
Merged
Conversation
Claude Code truncates hook stdout/additionalContext at 10,000 characters. On this repo (380 files) session-start printed 17,134 bytes, so the tree was cut mid-directory and the hubs, diff and handoff after it were lost. session-start now captures the header and trailer first, reserves their size (trailer capped at half the budget), and re-renders the tree at decreasing depth until the whole output fits, noting the depth it settled on. If depth 1 is still too large the tree is cut at a line boundary. The cap is limits.MaxHookOutputBytes, overridable with CODEMAP_HOOK_OUTPUT_CAP; the multi-repo path uses the same cap. captureStdout is extracted from emitCodexHookContext and reused. Closes #288 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWQw8AjoCA1yjN3T59vk46
There was a problem hiding this comment.
🟡 Changes recommended
The change still has two active output-size bugs: multi-repository output can exceed the configured cap, and very small positive caps can produce output larger than maxBytes.
2 open issues
What changed in this PR
This pull request constrains session-start hook output to a configurable 10,000-character cap while preserving important trailer context such as hubs, diffs, and impact information.
Changes:
- Adds the default
MaxHookOutputByteslimit andCODEMAP_HOOK_OUTPUT_CAPoverride. - Budgets header, tree, and trailer output together, reducing tree depth or truncating at line boundaries when necessary.
- Updates multi-repository handling and documents the new behavior.
- Adds tests for depth reduction, truncation, and oversized output.
| File | Description |
|---|---|
limits/limits.go |
Defines the default hook output cap. |
docs/HOOKS.md |
Documents session-start budgeting and the environment override. |
cmd/hooks.go |
Captures, fits, truncates, and emits session-start output, including multi-repository handling. |
cmd/hooks_more_test.go |
Tests output fitting, depth reduction, line-boundary truncation, and oversized trailers. |
Review effort: Lite
fitSessionStart could exceed maxBytes when the remaining tree budget was smaller than the depth notice (any small CODEMAP_HOOK_OUTPUT_CAP), since the header and notice were appended uncapped. The notice is now dropped when it does not fit and the assembled output gets a final line cut at maxBytes. The multi-repo path only charged each child's tree against the total; the header, setup hints, separators and truncation suffix were printed outside the accounting. It now builds the whole output, sizes each repo's budget from what is left (reserving room for the "more repos" line) and applies a final cut at the cap. indexOf is no longer used. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWQw8AjoCA1yjN3T59vk46
Resolves cmd/hooks.go against #290: keep emitHookContext (no CODEX gate) built on captureStdout. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWQw8AjoCA1yjN3T59vk46
JordanCoin
added a commit
that referenced
this pull request
Nov 6, 2026
Resolves cmd/hooks.go against #291: the collapsed package hub list now renders inside the captured session-start trailer. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWQw8AjoCA1yjN3T59vk46
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Closes #288.
codemap hook session-startprinted 17,134 bytes on this repository; Claude Code caps hook stdout at 10,000 characters, so the tree was cut mid-directory and the hubs, diff and intent trailer after it were lost.limits/limits.go:MaxHookOutputBytes = 10000;CODEMAP_HOOK_OUTPUT_CAPoverrides it.cmd/hooks.gofitSessionStart: header and trailer rendered first (trailer capped at half the budget), tree re-rendered at decreasing depth until it fits, notice line(tree limited to depth N to fit the 10000-char hook cap; run codemap . for the full tree). If depth 1 is still too big the tree is cut at a line boundary. Multi-repo path uses the same cap.TestFitSessionStartStaysUnderHookCapwith a synthetic tree growing tenfold per level.On this repo: 17,134 -> 5,135 bytes; hubs, diff vs main and impact warnings all survive. It lands well under the cap because depth 2 is 14 KB (scanner/ is wide), so it steps to a complete depth-1 tree. A later refinement could collapse only the widest directory instead.
Known: multi-repo loop checks the total before each repo so can overshoot by one repo's share; Codex JSON escaping is not budgeted. Conflicts with #287 around the stdout-capture helper; whichever merges second rebases.
go test ./cmd/ ./render/ ./limits/ ./config/,gofmt -lclean.🤖 Generated with Claude Code
https://claude.ai/code/session_01FWQw8AjoCA1yjN3T59vk46