feat: add react_remove tool for removing emoji reactions

[oskarszoon]

Summary

• Adds a react_remove channel tool that sends OutboundResponse::RemoveReaction, allowing agents to remove emoji reactions they previously added to messages
• Mirrors the existing react tool structure — same lifecycle (added/removed with other channel tools), same parameter shape (single emoji)
• Enables the "react with 👀 → respond → clean up 👀" pattern that agents need for acknowledgment workflows

Motivation

The RemoveReaction variant already exists on OutboundResponse and is handled by the messaging adapters (Slack fully implements it via reactions_remove, others gracefully no-op). But there was no tool exposing it to agents — they could add reactions but never remove them.

Changes

File	Change
src/tools/react_remove.rs	New tool, mirrors ReactTool but sends RemoveReaction
prompts/en/tools/react_remove_description.md.j2	Tool description for agent prompt injection
src/tools.rs	Module registration, pub exports, wired into add_channel_tools() / remove_channel_tools()
src/prompts/text.rs	Prompt registry entry for tools/react_remove

Adapter support

Adapter	RemoveReaction support
Slack	Full (reactions_remove API)
Mattermost	Full
Discord	No-op
Telegram	No-op
Signal	Logs warning, drops

Adapter implementations for Discord/Telegram/Signal are out of scope for this PR — the plumbing is in place for when those platforms add support or workarounds are found.

Test plan

• cargo fmt --all passes
• No new compiler warnings from react_remove.rs
• Tested on Slack: agent reacts with 👀, responds, then removes reaction

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 2b3c2f47-229e-409d-924f-42e30c582487

📥 Commits

Reviewing files that changed from the base of the PR and between b7d5dd2 and 1cbd52d.

📒 Files selected for processing (4)

• prompts/en/tools/react_remove_description.md.j2
• src/prompts/text.rs
• src/tools.rs
• src/tools/react_remove.rs

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Walkthrough

A new "react_remove" tool has been added to enable removal of emoji reactions from messages. The implementation includes a new tool module, Jinja template prompt file, tool registration in the framework, and corresponding prompt lookup entry.

Changes

Cohort / File(s)	Summary
Prompt template prompts/en/tools/react_remove_description.md.j2	Added Jinja template file containing instruction text for the react_remove tool describing emoji reaction removal behavior.
Tool implementation src/tools/react_remove.rs	New module implementing ReactRemoveTool with Tool trait, handling emoji removal via OutboundResponse::RemoveReaction, including argument parsing, error handling, and JSON schema-based tool definition.
Tool registration and integration src/tools.rs, src/prompts/text.rs	Updated tool module to register ReactRemoveTool in add_channel_tools() and remove_channel_tools(), added public re-exports; updated prompt lookup to map tools/react_remove key to the new template file.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: adding a new react_remove tool for removing emoji reactions, which is the primary focus of this PR.
Description check	✅ Passed	The description is well-structured and directly related to the changeset, covering motivation, implementation details, adapter support, and test plan.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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