Tag: claude-code

Why your Claude tool call fails schema validation, in both flavours: the API rejecting your tool definition at request time, and Claude returning a tool_use block your runner cannot accept. Concrete fixes for each, with strict mode, oneOf/anyOf, additionalProperties, and the retry loop pattern.

Why your Model Context Protocol server gets stuck in 'connecting' from Claude Code 2.x and never registers any tools. Covers stdout pollution, the npx install prompt, MCP_TIMEOUT, buffered output, and WSL pitfalls, with verifiable repros.

A 2026 walkthrough for wiring RAG into Claude Code 2.1.x: when agentic grep stops scaling, how to attach a hybrid BM25 + dense vector MCP server, how to wrap a retrieval CLI in a custom skill, and how Anthropic's contextual embeddings technique pushes recall above 92%. Anchored to claude-sonnet-4-6, claude-opus-4-7, and Claude Context 0.x.

A 2026 playbook for keeping Claude Code's 200k token context lean in a monorepo: launch from the subtree you are touching, split CLAUDE.md into nested files that load on demand, push path-scoped rules into .claude/rules/, use skills and subagents for the noisy reads, and exclude other teams' files with claudeMdExcludes. Anchored to Claude Code 2.1.x, claude-sonnet-4-6, and claude-opus-4-7.

Place rolling cache_control breakpoints across messages, respect the 20-block lookback, and refresh the 5-minute TTL automatically so a 50-turn agent loop pays the prefix once, not fifty times. Verified against anthropic 0.42 (Python) and @anthropic-ai/sdk 0.30 (Node) in May 2026.

Build a working LLM-as-judge eval harness for a coding agent in Python: golden tasks, deterministic checks, a rubric judge on Claude Sonnet 4.6, calibration against human labels, and a CI gate that fails the build when scores regress.

Cursor is the best place to plan a refactor. Aider is the best place to execute it from a terminal with cheap models and atomic git commits. This guide shows the exact pipe: dump the Cursor chat to markdown, hand it to Aider as a read-only context file, and run an architect/editor split that finishes the work.

Build a project-scoped Claude Code subagent that drives Playwright in a real browser, scoped to its own MCP server so the main session never sees the 25 browser_* tools. Covers the .claude/agents/browser-tester.md frontmatter, mcpServers inline definition, allowed tool list, isolation: worktree, the Playwright Test Agents init flow, and the Sonnet-vs-Haiku model choice.

Turn the unwritten rules in your repo into a SKILL.md that GitHub Copilot loads on demand. Frontmatter, descriptions that route, file references, and how to verify it actually fires.

Claude Code v2.1.128 (May 4, 2026) ships --plugin-dir support for .zip archives, makes EnterWorktree branch from local HEAD, and stops the CLI from leaking its own OTLP endpoint into Bash subprocesses.