fix(skill): support YAML array format for allowed-tools field (#1163)

Fixes #1021

The allowed-tools field in skill frontmatter now supports both formats:
- Space-separated string: 'allowed-tools: Read Write Edit Bash'
- YAML array: 'allowed-tools: [Read, Write, Edit, Bash]'
- Multi-line YAML array format also works

Previously, skills using YAML array format would silently fail to parse,
causing them to not appear in the <available_skills> list.

Changes:
- Updated parseAllowedTools() in loader.ts, async-loader.ts, and merger.ts
  to handle both string and string[] types
- Updated SkillMetadata type to accept string | string[] for allowed-tools
- Added 4 test cases covering all allowed-tools formats

src/features/opencode-skill-loader/async-loader.ts

@@ -128,8 +128,15 @@ $ARGUMENTS
   }
 }
 
-function parseAllowedTools(allowedTools: string | undefined): string[] | undefined {
+function parseAllowedTools(allowedTools: string | string[] | undefined): string[] | undefined {
   if (!allowedTools) return undefined
+  
+  // Handle YAML array format: already parsed as string[]
+  if (Array.isArray(allowedTools)) {
+    return allowedTools.map(t => t.trim()).filter(Boolean)
+  }
+  
+  // Handle space-separated string format: "Read Write Edit Bash"
   return allowedTools.split(/\s+/).filter(Boolean)
 }
 

src/features/opencode-skill-loader/loader.test.ts

@@ -268,6 +268,123 @@ Skill body.
       } finally {
         process.chdir(originalCwd)
       }
+      })
+  })
+
+  describe("allowed-tools parsing", () => {
+    it("parses space-separated allowed-tools string", async () => {
+      // #given
+      const skillContent = `---
+name: space-separated-tools
+description: Skill with space-separated allowed-tools
+allowed-tools: Read Write Edit Bash
+---
+Skill body.
+`
+      createTestSkill("space-separated-tools", skillContent)
+
+      // #when
+      const { discoverSkills } = await import("./loader")
+      const originalCwd = process.cwd()
+      process.chdir(TEST_DIR)
+
+      try {
+        const skills = await discoverSkills({ includeClaudeCodePaths: false })
+        const skill = skills.find(s => s.name === "space-separated-tools")
+
+        // #then
+        expect(skill).toBeDefined()
+        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
+      } finally {
+        process.chdir(originalCwd)
+      }
+    })
+
+    it("parses YAML inline array allowed-tools", async () => {
+      // #given
+      const skillContent = `---
+name: yaml-inline-array
+description: Skill with YAML inline array allowed-tools
+allowed-tools: [Read, Write, Edit, Bash]
+---
+Skill body.
+`
+      createTestSkill("yaml-inline-array", skillContent)
+
+      // #when
+      const { discoverSkills } = await import("./loader")
+      const originalCwd = process.cwd()
+      process.chdir(TEST_DIR)
+
+      try {
+        const skills = await discoverSkills({ includeClaudeCodePaths: false })
+        const skill = skills.find(s => s.name === "yaml-inline-array")
+
+        // #then
+        expect(skill).toBeDefined()
+        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
+      } finally {
+        process.chdir(originalCwd)
+      }
+    })
+
+    it("parses YAML multi-line array allowed-tools", async () => {
+      // #given
+      const skillContent = `---
+name: yaml-multiline-array
+description: Skill with YAML multi-line array allowed-tools
+allowed-tools:
+  - Read
+  - Write
+  - Edit
+  - Bash
+---
+Skill body.
+`
+      createTestSkill("yaml-multiline-array", skillContent)
+
+      // #when
+      const { discoverSkills } = await import("./loader")
+      const originalCwd = process.cwd()
+      process.chdir(TEST_DIR)
+
+      try {
+        const skills = await discoverSkills({ includeClaudeCodePaths: false })
+        const skill = skills.find(s => s.name === "yaml-multiline-array")
+
+        // #then
+        expect(skill).toBeDefined()
+        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
+      } finally {
+        process.chdir(originalCwd)
+      }
+    })
+
+    it("returns undefined for skill without allowed-tools", async () => {
+      // #given
+      const skillContent = `---
+name: no-allowed-tools
+description: Skill without allowed-tools field
+---
+Skill body.
+`
+      createTestSkill("no-allowed-tools", skillContent)
+
+      // #when
+      const { discoverSkills } = await import("./loader")
+      const originalCwd = process.cwd()
+      process.chdir(TEST_DIR)
+
+      try {
+        const skills = await discoverSkills({ includeClaudeCodePaths: false })
+        const skill = skills.find(s => s.name === "no-allowed-tools")
+
+        // #then
+        expect(skill).toBeDefined()
+        expect(skill?.allowedTools).toBeUndefined()
+      } finally {
+        process.chdir(originalCwd)
+      }
     })
   })
 })

src/features/opencode-skill-loader/loader.ts

@@ -50,8 +50,15 @@ async function loadMcpJsonFromDir(skillDir: string): Promise<SkillMcpConfig | un
   return undefined
 }
 
-function parseAllowedTools(allowedTools: string | undefined): string[] | undefined {
+function parseAllowedTools(allowedTools: string | string[] | undefined): string[] | undefined {
   if (!allowedTools) return undefined
+  
+  // Handle YAML array format: already parsed as string[]
+  if (Array.isArray(allowedTools)) {
+    return allowedTools.map(t => t.trim()).filter(Boolean)
+  }
+  
+  // Handle space-separated string format: "Read Write Edit Bash"
   return allowedTools.split(/\s+/).filter(Boolean)
 }
 

src/features/opencode-skill-loader/merger.ts

@@ -9,6 +9,14 @@ import { parseFrontmatter } from "../../shared/frontmatter"
 import { sanitizeModelField } from "../../shared/model-sanitizer"
 import { deepMerge } from "../../shared/deep-merge"
 
+function parseAllowedToolsFromMetadata(allowedTools: string | string[] | undefined): string[] | undefined {
+  if (!allowedTools) return undefined
+  if (Array.isArray(allowedTools)) {
+    return allowedTools.map(t => t.trim()).filter(Boolean)
+  }
+  return allowedTools.split(/\s+/).filter(Boolean)
+}
+
 const SCOPE_PRIORITY: Record<SkillScope, number> = {
   builtin: 1,
   config: 2,
@@ -119,7 +127,7 @@ $ARGUMENTS
   }
 
   const allowedTools = entry["allowed-tools"] ||
-    (fileMetadata["allowed-tools"] ? fileMetadata["allowed-tools"].split(/\s+/).filter(Boolean) : undefined)
+    (fileMetadata["allowed-tools"] ? parseAllowedToolsFromMetadata(fileMetadata["allowed-tools"]) : undefined)
 
   return {
     name,

src/features/opencode-skill-loader/types.ts

@@ -13,7 +13,7 @@ export interface SkillMetadata {
   license?: string
   compatibility?: string
   metadata?: Record<string, string>
-  "allowed-tools"?: string
+  "allowed-tools"?: string | string[]
   mcp?: SkillMcpConfig
 }