Claude Code goes silent for 10+ minutes in status=requesting after a tool_result with is_error=true

Summary

When a tool call returns a tool_result with is_error: true, Claude Code transitions to system:status:requesting and then emits no further stream-json output for at least 10 minutes — until the parent process eventually kills it. From the outside (a host MCP integration watching the stream-json output) there is no way to distinguish "agent is taking a long time to think" from "agent is wedged retrying upstream forever".

This is independent of the underlying tool-call failure cause: it reproduces against MCP -32000 Connection closed, against a fast-failing tool that returns is_error: true cleanly, and (per local triage) against unrelated upstream Anthropic 500s. The common factor is is_error=true arriving as the latest tool result.

Environment

• Claude Code: shipped via @anthropic-ai/claude-code, running as Paperclip's claude_local adapter (stdio + stream-json)
• Platform: macOS Darwin 24.6.0 x86_64
• Reference Paperclip run id: 71a50276-3695-48f4-bc0e-6a97b4581151
• Production rate: 40 of 68 claude_local heartbeat failures in a 48h sample matched this signature (28 via OK-tool-result chain that later failed, 8 via MCP -32000, 4 via tool-side is_error=true).

Reproduction

Any setup that produces a tool_result is_error=true in the stream should reproduce. From a real run:

00:35:21Z  assistant  tool_use mcp__context-mode__ctx_execute(...)
00:35:42Z  user       tool_result is_error=true content="MCP error -32000: Connection closed"
00:35:42Z  system     status=requesting
[no further stream events for ~10 minutes]
00:45:42Z  parent process SIGTERM (Paperclip 10-min watchdog)

Why this matters for MCP hosts

Stream-json is the contract a host process uses to tell whether Claude Code is making progress. After status=requesting, the next expected stream event is one of:

• assistant.message (Claude responding with text or another tool_use), or
• a system error / status change, or
• a result terminal event

When none of those arrive — for ten minutes — every host integration that watches stream-json runs a watchdog timer and kills the process. The agent's actual state in that ten minutes (retrying upstream? hung on a single request? deadlocked? waiting on a slow API?) is invisible.

What I think is happening (best guess)

After receiving is_error=true, Claude Code probably issues a request to the Anthropic API to generate a recovery response. Either:

1. That API call hangs / times out silently. No retry/timeout/error event is emitted to stream-json while this is happening. Recently saw an unrelated batch of these resolve after a Claude Code re-login (Anthropic auth refresh), so expired/stale auth tokens may be one path that lands here.
2. The API responds with another tool_use that also fails, and Claude Code enters a tight retry loop without flushing intermediate state to stream-json.

Either path needs to surface something to the stream — even a periodic heartbeat — for host integrations to tell thinking from dead.

What I'd ask for

Pick one (or both):

1. Periodic heartbeat in requesting state. Emit a system:status line every N seconds (5? 10?) while in requesting, so hosts can tell the agent is alive even if the upstream API is slow. A simple {"type":"system","subtype":"status","status":"requesting","elapsed_ms":12345} would solve this.
2. Hard timeout on requesting with a stream event when fired. If a single Anthropic API call exceeds some configured budget (default 60s? 120s?), emit a system:error or result line and either retry visibly or surface a terminal failure to the stream.

Either change would let host integrations like Paperclip distinguish slow-but-alive from dead-and-needs-killing without the current 10-minute SIGTERM cliff.

Related

Filed alongside #47378 (the -32000 Connection closed family); the two often co-occur — the transport drop trips is_error=true, then this silent-requesting behaviour kicks in. They are distinct bugs though: this one reproduces against any is_error=true cause, not just MCP transport drops. Tracking on our side as pcli-8ms AC2.