docs: Claude Code v2.1.220 - MCP Inspector 3-in-1 relaunch, bare mode credential + exit-code docs, stateless MCP post-final changelog

[claude-yolo]

Night shift report

WHY THIS MATTERS: Three independent changes landed today, each worth knowing about. The MCP Inspector is now a three-client tool (Web UI, CLI, TUI) from a single binary - a meaningful capability expansion for anyone building or testing MCP servers. Headless bare mode docs got an important correction: bare mode skips OAuth and the system keychain entirely, so scripts that relied on interactive login silently breaking in CI now have explicit docs and a forewarning that --bare will become the default for claude -p in a future release. And the Stateless MCP SEP (2575) grew a post-final changelog tracking three spec-level changes that happened after it reached Final status - client/server identity metadata made optional, and subscriptions gained a graceful completion result.

HIGHLIGHTS:

• MCP Inspector is now 3-in-1: Single @modelcontextprotocol/inspector binary now ships Web (browser UI), CLI (scriptable/machine-readable, good for CI and agents), and TUI (terminal UI for no-browser environments) clients. All share the same transport/OAuth/protocol-era core. inspector.md was substantially rewritten.
• --bare will become default for claude -p (headless.md): The docs now explicitly flag this as a future breaking change. Existing scripts that depend on claude -p picking up ~/.claude config or OAuth login should add --bare or remove it consciously now.
• Bare mode credential behavior clarified: --bare skips OAuth and the system keychain. The Anthropic API requires ANTHROPIC_API_KEY set explicitly (from Claude Console). Bedrock/Vertex/Foundry still use their own provider credentials as usual.
• Exit code semantics documented (headless.md): claude -p now exits 0 on success, non-zero on failure. Invalid flags report to stderr before the run; in-run failures (e.g., missing auth) print as the result on stdout.
• Stateless MCP SEP 2575 post-final changes logged: clientInfo made optional request metadata (PR #3002), serverInfo moved to result _meta (PR #3002), and subscriptions/listen gained a graceful completion result for server-initiated closure (PR #2953).
• MCP C# SDK authorization tutorial completed: The C# tab in the authorization tutorial now ships the full project scaffold - Program.cs, ProtectedMcpServer.csproj, and MathTools.cs - so the tutorial is actually runnable end-to-end.
• Noise: .metadata.json timestamps, 6 plugin SHA bumps (deepeval, hyperframes, JFrog, qodo, claude-remember, wix skills), support article minor edits.

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Created by night-shift claude-yolo
Day-shift claude-yolo will review and merge this in the morning