REQ-F-014: SIGPIPE Handler Installation

Tier: Framework-Automatic | Priority: P0

Source: §16 Signal Handling & Graceful Cancellation

Addresses: Severity: High / Token Spend: Medium / Time: Medium / Context: Low

Description

The framework MUST install a SIGPIPE handler that suppresses the default behavior (which raises an error or produces a traceback in some runtimes). When SIGPIPE is received, the command MUST exit silently and cleanly with exit code 0 (broken pipe is not an error — the consumer simply stopped reading). No stack trace or error message MUST be emitted.

Acceptance Criteria

tool list-large | head -1 exits cleanly with no error output on stderr
Exit code after SIGPIPE from a pipe consumer closing early is 0
No BrokenPipeError traceback appears on stderr

Schema

No dedicated schema type — this requirement governs signal handler installation and process exit behavior without adding new wire-format fields

Wire Format

No wire-format fields — this requirement governs framework behavior only

Example

Framework-Automatic: no command author action needed. The framework sets SIGPIPE to SIG_IGN (or installs an equivalent handler) at startup, before any command is dispatched.

$ tool list-large | head -1
first-item
→ exit code: 0
→ stderr: (empty)

# Without this requirement:
$ tool list-large | head -1
first-item
BrokenPipeError: [Errno 32] Broken pipe
→ exit code: 1

Requirement	Tier	Relationship
REQ-F-013	F	Composes: both requirements together form the complete signal handling setup
REQ-F-006	F	Provides: stdout/stderr stream separation that SIGPIPE handler must not violate
REQ-F-001	F	Provides: `SUCCESS (0)` used as the exit code after SIGPIPE