feat(hooks): emit session prune lifecycle event by vincentkoc · Pull Request #12581 · openclaw/openclaw

vincentkoc · 2026-02-09T10:34:08Z

Why

Context pruning changes model input quality and cost, but there was no dedicated internal lifecycle signal for pruning actions. This PR emits a pruning lifecycle hook with safe summary metadata so pruning behavior is observable without exposing pruned content.

Closes #8606

Detailed Changes

Added internal lifecycle event:
- session:prune
Pruning hook context includes summary metadata:
- softTrimmedCount
- hardClearedCount
- toolNames
- sessionId (when available)
Updated context-pruning extension/pruner tests for async path + hook emission behavior

Greptile Overview

Greptile Summary

This PR adds a new internal hook lifecycle event, session:prune, emitted by the context pruning path. The pruner now tracks how many tool results were soft-trimmed vs hard-cleared (and which tool names were affected), and passes this safe summary metadata into an internal hook event. The context-pruning extension’s context handler was updated to be async to await pruning, and tests were updated to cover the async path and hook emission behavior.

Within the codebase, this integrates into the existing internal hook system (src/hooks/internal-hooks.ts) by creating and triggering an InternalHookEvent of type session and action prune, keyed by a derived session key.

Confidence Score: 4/5

This PR is mostly safe to merge, but there is one correctness issue around the emitted hook event timestamp semantics that should be clarified/fixed.
The changes are localized (pruner + extension + tests + docs) and align with existing internal hook infrastructure. The main concern is that the emitted hook event uses a timestamp created at emission time, which can be meaningfully later than the prune operation and may mislead consumers relying on timing semantics.
src/agents/pi-extensions/context-pruning/pruner.ts

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-02-09T10:42:14Z

Additional Comments (1)

src/agents/pi-extensions/context-pruning/pruner.ts
Missing prune hook emission
When prunableToolChars < settings.minPrunableToolChars, the function returns outputAfterSoftTrim without calling emitPruneHook(). In that scenario, earlier soft-trims may have happened (and counts/tool names are tracked), but the new session:prune lifecycle event will never be emitted. If the intent is “emit whenever any pruning occurred”, this early return breaks observability.

This affects the minPrunableToolChars guard path specifically (pruning happens, but total prunable chars is below the threshold).

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/agents/pi-extensions/context-pruning/pruner.ts
Line: 345:355

Comment:
**Missing prune hook emission**
When `prunableToolChars < settings.minPrunableToolChars`, the function returns `outputAfterSoftTrim` without calling `emitPruneHook()`. In that scenario, earlier soft-trims may have happened (and counts/tool names are tracked), but the new `session:prune` lifecycle event will never be emitted. If the intent is “emit whenever any pruning occurred”, this early return breaks observability.

This affects the `minPrunableToolChars` guard path specifically (pruning happens, but total prunable chars is below the threshold).

How can I resolve this? If you propose a fix, please make it concise.

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning/pruner.ts

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning.test.ts

greptile-apps · 2026-02-09T19:12:32Z

Additional Comments (1)

src/agents/pi-extensions/context-pruning.test.ts, line 24
Mock path likely wrong

This test mocks "../../hooks/internal-hooks.js", but pruner.ts imports the hook module via "../../../hooks/internal-hooks.js" (from src/agents/pi-extensions/context-pruning/pruner.ts). If Vitest resolves these as different module IDs, the mock won’t apply and triggerInternalHook assertions will be calling the real implementation (or not be observed at all). Safer to mock the same specifier the code under test uses (or mock by absolute/alias path used across the repo) so the hook spy is guaranteed to intercept the import.

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning.test.ts

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning/pruner.ts

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning/pruner.ts

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

src/agents/pi-extensions/context-pruning/pruner.ts

feat(hooks): emit session prune lifecycle event

cb286f5

openclaw-barnacle bot added the agents Agent runtime and tooling label Feb 9, 2026

vincentkoc marked this pull request as ready for review February 9, 2026 10:41

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

fix(hooks): always emit prune event after soft trims

ab60de4

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning/pruner.ts Show resolved Hide resolved

docs(hooks): document prune lifecycle event

ab3f711

vincentkoc marked this pull request as draft February 9, 2026 16:44

openclaw-barnacle bot added the docs Improvements or additions to documentation label Feb 9, 2026

fix(hooks): await session prune hook emission

620befb

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning.test.ts Show resolved Hide resolved

test(hooks): mock internal hooks by both specifiers

caf3ce1

vincentkoc marked this pull request as ready for review February 9, 2026 19:32

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning.test.ts Show resolved Hide resolved

test(hooks): match importActual specifier for internal hooks mock

23edc8a

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning/pruner.ts Outdated Show resolved Hide resolved

fix(hooks): skip prune hook without session identity

97935d8

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning/pruner.ts Outdated Show resolved Hide resolved

vincentkoc marked this pull request as draft February 9, 2026 20:00

vincentkoc added 2 commits February 9, 2026 12:33

Merge branch 'main' into vincentkoc-code/hooks-pruning-event

fa066b7

refactor(hooks): make prune session key trimming explicit

1396213

vincentkoc marked this pull request as ready for review February 9, 2026 21:44

greptile-apps bot reviewed Feb 9, 2026

View reviewed changes

src/agents/pi-extensions/context-pruning/pruner.ts Show resolved Hide resolved

vincentkoc added 2 commits February 9, 2026 13:58

Merge branch 'main' into vincentkoc-code/hooks-pruning-event

f3544e8

fix(hooks): record deterministic prune event timing

7e85b4f

This was referenced Feb 9, 2026

feat(hooks): fixed and adding various agent, messaging, system and compaction hooks #9761

Closed

Plugin hooks exist in type system but some are never called in execution flow #6535

Closed

thewilloftheshadow force-pushed the main branch from bfc1ccb to f92900f Compare February 15, 2026 18:46

Uh oh!

Conversation

vincentkoc commented Feb 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Why

Detailed Changes

Related Links and Issues

Greptile Overview

Greptile Summary

Confidence Score: 4/5

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

greptile-apps bot commented Feb 9, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot commented Feb 9, 2026

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

greptile-apps bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Comments

vincentkoc commented Feb 9, 2026 •

edited

Loading