feat: Add built-in skill for goose documentation reference

crates/goose/src/agents/builtin_skills/goose_doc_guide.md

@@ -0,0 +1,59 @@
+---
+name: goose-doc-guide
+description: Reference goose documentation to create, configure, or explain goose-specific features like recipes, extensions, sessions, and providers. You MUST fetch relevant goose docs before answering. You MUST NOT rely on training data or assumptions for any goose-specific fields, values, names, syntax, or commands.
+---
+
+Use this skill when working with **goose-specific features**:
+- Creating or editing recipes
+- Configuring extensions or providers
+- Explaining how goose features work
+- Any goose configuration or setup task
+
+Do NOT use this skill for:
+- General coding tasks unrelated to goose
+- Running existing recipes (just run them directly)
+
+## Steps (COMPLETE ALL BEFORE RESPONDING)
+1. **Fetch official docs**
+   - Fetch the doc map from `https://block.github.io/goose/goose-docs-map.md`
+   - Search the doc map for pages relevant to the user's topic and get the paths for these pages
+   - Use the EXACT paths from the doc map. For example:
+   - If doc map shows: `docs/guides/sessions/session-management.md`
+   - Fetch: `https://block.github.io/goose/docs/guides/sessions/session-management.md`
+   - Do NOT modify or guess paths. 
+   - **ONLY fetch paths that are explicitly listed in the doc map - do not guess or infer URLs**
+   - Make multiple fetch calls in parallel and save to temp files
+   - Use the temp files for subsequent searches instead of re-fetching
+
+2. **Create/modify content**
+   - For goose configuration files:
+      - Consult schema/field reference documentation first
+      - **Search the fetched docs to extract the complete schema for each element you plan to use**
+      - Extract example snippets to understand usage patterns
+      - Create your configuration based on reference specs, following example patterns
+      - **⚠️ STOP: Before showing the user, verify output content MUST match the schema and reference in goose the official documentation:**
+         - [ ] Field names match exactly as shown in docs
+         - [ ] Required fields/properties are present
+         - [ ] Value formats match examples (YAML/JSON syntax, data types, etc.)
+      - **If ANY verification fails, revise and repeat this step until ALL verifications pass**
+      - **DO NOT present unverified output to the user**
+   - Use only fetched docs for all goose-specific details
+
+3. **MANDATORY VERIFICATION - DO THIS BEFORE STEP 4**
+   Before writing your final answer:
+   - [ ] You ONLY present goose-specific information that is explicitly stated in the fetched documentation. If you cannot identify the documentation page that supports a detail, you must NOT include it.
+   - [ ] add instructions/commands if: (a) user explicitly asked for them, AND (b) they appear in the fetched docs
+   - You MUST NOT rely on training data or assumptions for any goose-specific fields, values, names, syntax, or commands.
+   - [ ] For EVERY goose-specific command in your answer: Search feteched files to verify it exists
+   - [ ] For EVERY goose-specific field in your answer: Search feteched files to verify it exists  
+   - [ ] For EVERY usage instruction in your answer: Search feteched files to verify it exists
+   - [ ] If you cannot verify something: Remove it, unless the user explicitly asked for it (then state "I could not find documentation for [X]")
+
+4. **Provide your answer and include a "Verification Completed" section showing which checks passed**
+   - Which checks passed
+   - How you verified each field exists in the documentation
+
+5. **List documentation links**
+   - Only include docs actually used
+   - Remove `.md` suffix from URLs
+   - Example: If you fetched `https://block.github.io/goose/docs/guides/sessions/session-management.md`, list it as `https://block.github.io/goose/docs/guides/sessions/session-management`

crates/goose/src/agents/builtin_skills/mod.rs

@@ -0,0 +1,11 @@
+use include_dir::{include_dir, Dir};
+
+static BUILTIN_SKILLS_DIR: Dir = include_dir!("$CARGO_MANIFEST_DIR/src/agents/builtin_skills");
+
+pub fn get_all_builtin_skills() -> Vec<&'static str> {
+    BUILTIN_SKILLS_DIR
+        .files()
+        .filter(|f| f.path().extension().is_some_and(|ext| ext == "md"))
+        .filter_map(|f| f.contents_utf8())
+        .collect()
+}

crates/goose/src/agents/mod.rs

@@ -1,4 +1,5 @@
 mod agent;
+mod builtin_skills;
 pub(crate) mod chatrecall_extension;
 pub(crate) mod code_execution_extension;
 pub mod execute_commands;

crates/goose/src/agents/skills_extension.rs

@@ -1,3 +1,4 @@
+use super::builtin_skills;
 use crate::agents::extension::PlatformExtensionContext;
 use crate::agents::mcp_client::{Error, McpClientTrait, McpMeta};
 use crate::config::paths::Paths;
@@ -64,17 +65,38 @@ impl SkillsClient {
             instructions: Some(String::new()),
         };
 
+        let mut skills = Self::load_builtin_skills();
+
         let directories = Self::get_default_skill_directories()
             .into_iter()
             .filter(|d| d.exists())
             .collect::<Vec<_>>();
-        let skills = Self::discover_skills_in_directories(&directories);
+        let fs_skills = Self::discover_skills_in_directories(&directories);
+        skills.extend(fs_skills);
 
         let mut client = Self { info, skills };
         client.info.instructions = Some(client.generate_instructions());
         Ok(client)
     }
 
+    fn load_builtin_skills() -> HashMap<String, Skill> {
+        let mut skills = HashMap::new();
+        for content in builtin_skills::get_all_builtin_skills() {
+            if let Ok((metadata, body)) = Self::parse_frontmatter(content) {
+                skills.insert(
+                    metadata.name.clone(),
+                    Skill {
+                        metadata,
+                        body,
+                        directory: PathBuf::new(),
+                        supporting_files: vec![],
+                    },
+                );
+            }
+        }
+        skills
+    }
+
     fn get_default_skill_directories() -> Vec<PathBuf> {
         let mut dirs = Vec::new();
 
@@ -826,4 +848,12 @@ Working dir goose content
             .body
             .contains("Working dir goose content"));
     }
+
+    #[test]
+    fn test_builtin_skills_loaded() {
+        let skills = SkillsClient::load_builtin_skills();
+
+        assert!(!skills.is_empty());
+        assert!(skills.contains_key("goose-doc-guide"));
+    }
 }