feat: implement SKILLS.md - claude compatibility.

[michaelneale]

This is implemented as a almost trivial platform extension (similar to todo, chatrecall) which can be opted in or out of, and follows the spec to keep the overhead very tiny, and load the skill (itself) as a single simple tool call.

Testing notes:

add a skill to ~/.goose/config/skills/SKILL.md with:

---
name: your-skill-name
description: Brief description of what this Skill does and when to use it
---

# Your Skill Name

## Instructions
say hello world

and then ask it about skills, or to do something that could use your skill.

#5761 for discussion on this feature.

[Copilot]

Pull Request Overview

This PR implements SKILLS.md support for Claude compatibility as a platform extension, enabling Goose to discover and load skill definitions from .claude/skills or .goose/skills directories.

• Adds a new skills platform extension that follows the same pattern as existing extensions (todo, chatrecall)
• Implements SKILL.md file parsing with YAML frontmatter for metadata
• Provides a loadSkill tool for on-demand skill loading with supporting file discovery

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
crates/goose/src/agents/skills_extension.rs	New file implementing the skills extension with skill discovery, YAML frontmatter parsing, and MCP client trait implementation
crates/goose/src/agents/extension.rs	Registers the skills extension in the platform extensions map with default enabled
crates/goose/src/agents/mod.rs	Adds module declaration for skills_extension with crate visibility
crates/goose/src/config/extensions.rs	Minor whitespace formatting change

[codefromthecrypt]

I haven't tried this, but the code looks clean and easy to iterate forward. I think if we end up with fancy skills (e.g. want to test something end-to-end like that includes a shell script) we indeed would want that in a follow-up PR.

I made some comments which are non-blocking

[vaibhavgeek]

Hi,

I created the skill file by creating a file called ECHO.md

user@Users-MacBook-Pro skills % cat ECHO.md
---
name: echo
description: Brief description of what this Skill does and when to use it
---

# Your Skill Name
Echo
## Instructions
say wabba labba dub dub for any input
user@Users-MacBook-Pro skills % pwd
/Users/user/.goose/config/skills
user@Users-MacBook-Pro skills %

Screenshot from the UI

The response says it is not able to find any skills though.
Logs:

18:20:16.800 › goosed stderr for port 59625 and dir /Users/user:     in goose::agents::agent::dispatch_tool_call with cancellation_token: Some(CancellationToken { is_cancelled: false }), session: Session { id: "20251121_9", working_dir: "/Users/user", name: "New session 2", user_set_name: false, session_type: User, created_at: 2025-11-21T12:50:08Z, updated_at: 2025-11-21T12:50:09Z, extension_data: ExtensionData { extension_states: {} }, total_tokens: None, input_tokens: None, output_tokens: None, accumulated_total_tokens: None, accumulated_input_tokens: None, accumulated_output_tokens: None, schedule_id: None, recipe: None, user_recipe_values: None, conversation: Some(Conversation([Message { id: Some("msg_20251121_9_0"), role: User, created: 1763729409, content: [Text(Annotated { raw: RawTextContent { text: "run the skill echo", meta: None }, annotations: None })], metadata: MessageMetadata { user_visible: true, agent_visible: true } }])), message_count: 1 }
18:20:16.801 › goosed stderr for port 59625 and dir /Users/user:   2025-11-21T12:50:16.797790Z DEBUG goose::agents::agent: WAITING_TOOL_END: skills__loadSkill
18:20:16.801 › goosed stderr for port 59625 and dir /Users/user:     at crates/goose/src/agents/agent.rs:603
18:20:16.801 › goosed stderr for port 59625 and dir /Users/user:     in goose::agents::agent::dispatch_tool_call with cancellation_token: Some(CancellationToken { is_cancelled: false }), session: Session { id: "20251121_9", working_dir: "/Users/user", name: "New session 2", user_set_name: false, session_type: User, created_at: 2025-11-21T12:50:08Z, updated_at: 2025-11-21T12:50:09Z, extension_data: ExtensionData { extension_states: {} }, total_tokens: None, input_tokens: None, output_tokens: None, accumulated_total_tokens: None, accumulated_input_tokens: None, accumulated_output_tokens: None, schedule_id: None, recipe: None, user_recipe_values: None, conversation: Some(Conversation([Message { id: Some("msg_20251121_9_0"), role: User, created: 1763729409, content: [Text(Annotated { raw: RawTextContent { text: "run the skill echo", meta: None }, annotations: None })], metadata: MessageMetadata { user_visible: true, agent_visible: true } }])), message_count: 1 }
18:20:16.801 › goosed stderr for port 59625 and dir /Users/user:   2025-11-21T12:50:16.798074Z  INFO goosed::routes::reply: Tool call completed, counter.goose.tool_completions: 1, tool_name: skills__loadSkill, result: success
18:2

[michaelneale]

@vaibhavgeek you have to add it to ~/.goose/skills or ~/.claude/skills in a dir (any name) but the file MUST be SKILL.md, ECHO.md won't work as it looks for SKILL.md (this is claudes spec so really just following it - or trying to!).

[michaelneale]

thanks for feedback all - some more cleaning up to do. Only thing that makes me uncomfortable is if people use a lot of skills AND mcps, then it adds a bit more noise (this can be turned off, of course, wondering if default should be off, can always change that too).

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.