feat: wrap pipeline errors in SpmError with EINSTALL code

- Add INSTALL_ERROR (EINSTALL) error code
- fetchQueue processor wraps fetch failures in SpmError with skill name context
- linkQueue processor wraps link failures in SpmError with skill name context
- pipeline/index.ts aggregates multiple errors into single SpmError with list
- formatErrorForDisplay shows failed skill list for INSTALL_ERROR

Author: SoonIter

packages/skills-package-manager/src/errors/codes.ts

@@ -33,6 +33,9 @@ export enum ErrorCode {
   NETWORK_ERROR = 'ENETWORK',
   REPO_NOT_FOUND = 'EREPONOTFOUND',
 
+  // Install/Pipeline errors (6xx)
+  INSTALL_ERROR = 'EINSTALL',
+
   // General errors (9xx)
   UNKNOWN_ERROR = 'EUNKNOWN',
   NOT_IMPLEMENTED = 'ENOTIMPL',

packages/skills-package-manager/src/errors/index.ts

@@ -128,6 +128,14 @@ export function formatErrorForDisplay(error: unknown): string {
         output += `\n\nPlease fix the validation errors in "${error.filePath}".`
         output += `\nRefer to the JSON Schema at: https://unpkg.com/skills-package-manager@latest/skills.schema.json`
       }
+    } else if (error.code === ErrorCode.INSTALL_ERROR) {
+      const errorList = error.context.errors as string[] | undefined
+      if (errorList && errorList.length > 1) {
+        output += `\n\nFailed skills:`
+        for (const msg of errorList) {
+          output += `\n  - ${msg}`
+        }
+      }
     }
 
     if (error.cause && !(error instanceof GitError || error instanceof FileSystemError)) {

packages/skills-package-manager/src/pipeline/fetchQueue.ts

@@ -1,5 +1,6 @@
 import { access, lstat, readFile, readlink } from 'node:fs/promises'
 import path from 'node:path'
+import { ErrorCode, SpmError } from '../errors'
 import { fetchSkill } from '../fetchers'
 import { applySkillPatch } from '../patches/skillPatch'
 import { createTaskQueue, type TaskQueue } from './queue'
@@ -56,26 +57,35 @@ export function createFetchTaskQueue(
       return result
     }
 
-    const { installPath, fromCache } = await fetchSkill(
-      ctx.cwd,
-      task.skillName,
-      task.entry,
-      installDir,
-      ctx.cache,
-    )
+    try {
+      const { installPath, fromCache } = await fetchSkill(
+        ctx.cwd,
+        task.skillName,
+        task.entry,
+        installDir,
+        ctx.cache,
+      )
 
-    if (task.entry.patch) {
-      await applySkillPatch(installPath, path.resolve(ctx.cwd, task.entry.patch.path))
-    }
+      if (task.entry.patch) {
+        await applySkillPatch(installPath, path.resolve(ctx.cwd, task.entry.patch.path))
+      }
 
-    const result: FetchResult = {
-      skillName: task.skillName,
-      entry: task.entry,
-      installPath,
-      fromCache,
+      const result: FetchResult = {
+        skillName: task.skillName,
+        entry: task.entry,
+        installPath,
+        fromCache,
+      }
+      bus.emitFetched(result)
+      return result
+    } catch (error) {
+      throw new SpmError({
+        code: ErrorCode.INSTALL_ERROR,
+        message: `Failed to fetch skill "${task.skillName}": ${error instanceof Error ? error.message : String(error)}`,
+        cause: error instanceof Error ? error : undefined,
+        context: { skillName: task.skillName, phase: 'fetch' },
+      })
     }
-    bus.emitFetched(result)
-    return result
   }
 
   return createTaskQueue(processor, options)

packages/skills-package-manager/src/pipeline/index.ts

@@ -1,6 +1,7 @@
 import { access } from 'node:fs/promises'
 import path from 'node:path'
 import type { SkillsLock, SkillsLockEntry } from '../config/types'
+import { ErrorCode, SpmError } from '../errors'
 import { writeInstallState } from '../install/installState'
 import { pruneManagedSkills } from '../install/pruneManagedSkills'
 import { installStageHooks } from '../install/withBundledSelfSkillLock'
@@ -146,7 +147,16 @@ export async function runPipeline(input: RunPipelineInput): Promise<PipelineResu
   await linkQueue.drain()
 
   if (errors.length > 0) {
-    throw errors[0]
+    const first = errors[0]
+    if (errors.length === 1) {
+      throw first
+    }
+    throw new SpmError({
+      code: ErrorCode.INSTALL_ERROR,
+      message: `${errors.length} skills failed to install`,
+      cause: first instanceof Error ? first : undefined,
+      context: { errors: errors.map((e) => (e instanceof Error ? e.message : String(e))) },
+    })
   }
 
   const results = bus.getResults()

packages/skills-package-manager/src/pipeline/linkQueue.ts

@@ -1,3 +1,4 @@
+import { ErrorCode, SpmError } from '../errors'
 import { linkSkill } from '../install/links'
 import { createTaskQueue, type TaskQueue } from './queue'
 import type { LinkResult, LinkTask, PipelineBus, WorkspaceContext } from './types'
@@ -13,13 +14,22 @@ export function createLinkTaskQueue(
   const linkTargets = ctx.lockfile?.linkTargets ?? ctx.manifest.linkTargets ?? []
 
   async function processor(task: LinkTask): Promise<LinkResult> {
-    for (const linkTarget of linkTargets) {
-      await linkSkill(ctx.cwd, installDir, linkTarget, task.skillName)
-    }
+    try {
+      for (const linkTarget of linkTargets) {
+        await linkSkill(ctx.cwd, installDir, linkTarget, task.skillName)
+      }
 
-    const result: LinkResult = { skillName: task.skillName }
-    bus.emitLinked(result)
-    return result
+      const result: LinkResult = { skillName: task.skillName }
+      bus.emitLinked(result)
+      return result
+    } catch (error) {
+      throw new SpmError({
+        code: ErrorCode.INSTALL_ERROR,
+        message: `Failed to link skill "${task.skillName}": ${error instanceof Error ? error.message : String(error)}`,
+        cause: error instanceof Error ? error : undefined,
+        context: { skillName: task.skillName, phase: 'link' },
+      })
+    }
   }
 
   return createTaskQueue(processor, options)