fix: cache failed build output so gradle-get-details works for failures

[holloandris]

Problem

gradle-build throws BUILD_FAILED (in GradleAdapter.build) before handleGradleBuildTool generates a buildId or caches the output. So when a build fails:

• No buildId is produced and nothing is cached → gradle-get-details has nothing to fetch.
• The error's own "Check gradle-get-details for full error output" suggestion is a dead end for failures.
• No log file exists on disk (output is only ever kept in the in-memory cache, which the failure path skips).

The net effect: the build you most need to inspect — a failing one — is the only one whose full output you can't retrieve.

Fix

• Carry the full build output on the thrown error's context (fullOutput).
• In handleGradleBuildTool, catch BUILD_FAILED, cache { fullOutput, result, operation } under a fresh buildId (identical shape to the success path), and rethrow the same BUILD_FAILED error with that buildId in context — without inlining the bulky fullOutput, so the error payload stays small.

gradle-get-details { id, detailType: "errors" } now returns compiler errors for failed builds exactly as it does for successful ones. The error code/contract is unchanged; the token-optimized design is preserved (raw logs are fetched on demand, not dumped into the error).

Test

Adds a round-trip test: a failing gradle-build → assert it rethrows BUILD_FAILED with a buildId (and no inlined fullOutput) → feed that id to gradle-get-details and assert the compiler error line is returned.

Full suite (673 tests) + contract & token-snapshot checks pass.

[greptile-apps]

Greptile Summary

This PR fixes the gradle-get-details dead end for failing builds by caching the full build output before rethrowing BUILD_FAILED, giving it a buildId that clients can use to retrieve compiler errors — the same retrieval path as successful builds.

• GradleAdapter.build now attaches fullOutput to the thrown BUILD_FAILED error's context, so the tool handler can pull it out for caching.
• handleGradleBuildTool catches BUILD_FAILED, stores { fullOutput, result, operation } in the cache under a fresh buildId, then rethrows a new BUILD_FAILED error with only { buildResult, buildId } in context — fullOutput is intentionally stripped so the error payload remains small and never reaches the server's toToolError() serialiser.
• A new round-trip test validates the full failure → cache → retrieval flow.

Confidence Score: 5/5

Safe to merge — the change is self-contained and the rethrown error deliberately omits fullOutput so the MCP serialiser never sees the raw build log.

The failure-path catch block correctly caches output and rethrows a lean error; the success path is untouched; toToolError() on the rethrown error only exposes { buildResult, buildId }. The new round-trip test covers the critical path end-to-end and the shape of the cached entry matches exactly what gradle-get-details expects for every detailType.

No files require special attention.

Important Files Changed

Filename	Overview
src/tools/gradle-build.ts	Wraps the build call in a try/catch; on BUILD_FAILED caches the output and rethrows a new error with buildId but without fullOutput, keeping the MCP response payload small.
src/adapters/gradle.ts	Attaches fullOutput to the BUILD_FAILED error context so the tool layer can cache it; the original success-path return is unchanged.
src/types/errors.ts	Adds fullOutput and buildId to ErrorContext; minimal, non-breaking type extension.
tests/tools/gradle-build-failure.test.ts	New round-trip test covering BUILD_FAILED caching and retrieval via gradle-get-details; mock shape and assertions match the implementation correctly.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant Client
    participant Server as server.ts
    participant Tool as handleGradleBuildTool
    participant Adapter as GradleAdapter.build
    participant Cache as CacheManager

    Client->>Server: "gradle-build { operation, ... }"
    Server->>Tool: handleGradleBuildTool(input, context)
    Tool->>Adapter: context.gradle.build(operation, ...)
    Adapter-->>Tool: "throws BUILD_FAILED { buildResult, fullOutput }"

    Note over Tool: catch BUILD_FAILED
    Tool->>Cache: "cache.set(buildId, { fullOutput, result, operation })"
    Tool-->>Server: "rethrows BUILD_FAILED { buildResult, buildId } (no fullOutput)"
    Server-->>Client: "error { code: BUILD_FAILED, suggestion: gradle-get-details id }"

    Client->>Server: "gradle-get-details { id: buildId, detailType: errors }"
    Server->>Cache: cache.get(buildId)
    Cache-->>Server: "{ fullOutput, result, operation }"
    Server-->>Client: "{ detailType: errors, errors: ..., ... }"

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sequenceDiagram
    participant Client
    participant Server as server.ts
    participant Tool as handleGradleBuildTool
    participant Adapter as GradleAdapter.build
    participant Cache as CacheManager

    Client->>Server: "gradle-build { operation, ... }"
    Server->>Tool: handleGradleBuildTool(input, context)
    Tool->>Adapter: context.gradle.build(operation, ...)
    Adapter-->>Tool: "throws BUILD_FAILED { buildResult, fullOutput }"

    Note over Tool: catch BUILD_FAILED
    Tool->>Cache: "cache.set(buildId, { fullOutput, result, operation })"
    Tool-->>Server: "rethrows BUILD_FAILED { buildResult, buildId } (no fullOutput)"
    Server-->>Client: "error { code: BUILD_FAILED, suggestion: gradle-get-details id }"

    Client->>Server: "gradle-get-details { id: buildId, detailType: errors }"
    Server->>Cache: cache.get(buildId)
    Cache-->>Server: "{ fullOutput, result, operation }"
    Server-->>Client: "{ detailType: errors, errors: ..., ... }"

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_{Reviews (2): Last reviewed commit: "fix: cache failed build output so gradle..." | Re-trigger Greptile}