fix: remove <thinking> tags from prompts for cleaner output and fewer tokens

[roomote]

Summary

This PR addresses Issue #8318 by removing all references to <thinking> tags from prompts while preserving the underlying behavioral rules.

Changes

• Removed <thinking></thinking> tags from tool-use-guidelines.ts
• Removed <thinking></thinking> tags from objective.ts
• Removed <thinking></thinking> tags from attempt-completion.ts
• Updated test expectations to match the new prompt format
• Preserved the behavioral rule about confirming tool success in plain language

Benefits

• Cleaner prompts: Removes unnecessary markup that adds clutter
• Fewer tokens: Reduces token usage by eliminating redundant tags
• Better compatibility: Prevents models from treating tags as special syntax
• Clearer instructions: Core rules are now expressed directly without being buried in markup

Testing

• ✅ All existing tests pass
• ✅ Linting and type checking pass
• ✅ Review confidence: 95%

Fixes #8318

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Important

Removed <thinking> tags from prompts for cleaner output and fewer tokens, updating tests to match the new format.

• Behavior:
  • Removed <thinking></thinking> tags from tool-use-guidelines.ts, objective.ts, and attempt-completion.ts.
  • Updated test expectations in objective.spec.ts and tool-use-guidelines.spec.ts to match the new prompt format.
  • Preserved the behavioral rule about confirming tool success in plain language.
• Benefits:
  • Cleaner prompts by removing unnecessary markup.
  • Reduces token usage by eliminating redundant tags.
  • Prevents models from treating tags as special syntax.
  • Core rules are now expressed directly without being buried in markup.
• Testing:
  • All existing tests pass.
  • Linting and type checking pass.

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[roomote]

Self-review routine engaged: judging my own code with machine-like indifference to see if the tags truly vanished.

[roomote]

[P3] Clarity tweak: explicitly require "explicit confirmation" and block usage if any tool result is missing/unclear. This mirrors current behavior but reduces ambiguity for some models.

[Copilot]

Pull Request Overview

This PR removes all <thinking> tags from AI prompts to create cleaner output, reduce token usage, and prevent models from treating the tags as special syntax while preserving the underlying behavioral requirements.

• Replaced <thinking></thinking> tag references with direct analysis instructions
• Updated test expectations to match the new prompt format without thinking tags
• Maintained core behavioral rules about confirming tool success before proceeding

Reviewed Changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/core/prompts/tools/attempt-completion.ts	Removed thinking tag requirement from tool validation instructions
src/core/prompts/sections/tool-use-guidelines.ts	Changed thinking tag guidance to direct assessment instruction
src/core/prompts/sections/objective.ts	Replaced thinking tag analysis with plain analysis instruction
src/core/prompts/sections/tests/tool-use-guidelines.spec.ts	Updated test expectations to match new guideline format
src/core/prompts/sections/tests/objective.spec.ts	Updated test description and expectations for analysis guidance
Multiple snapshot files	Updated system prompt snapshots to reflect removed thinking tags

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