WEB-5004: attach referenced file contents to tool telemetry

[pugazhendhi-m]

What

Adds a uniform file_content field to the PreToolUse and PostToolUse/Stop telemetry payloads of all five coding-tool hooks (claude-code, cursor, codex, copilot, augment). For a file tool (Read/Write/Edit/MCP), the hook reads the referenced file and attaches:

file_content = [{ "path": ..., "content": ..., "truncated": <bool> }]

Uniform key + shape across every tool (single-file = 1-element list) so the gateway/backend can consume it identically.

How

• Shared helpers (_cap_file_text, _resolve_and_read_file, _make_file_entry, _attach_file_content) are byte-identical across all 5 hooks (per-tool parity).
• Write reuses the inline content (file may not exist on disk yet); Read/Edit read from disk, resolving relative paths against cwd (claude/cursor paths are already absolute).
• 64KB per-file cap, truncate + per-entry truncated flag.
• Wired at PRE (pre_tool_use_data.metadata) and POST (end-of-turn tool_use entries).

Safety / fail-open

• Never raises or blocks the editor. Missing / binary (\x00) / non-UTF8 / permission-denied / directory / unresolvable-relative-path all silently skip.
• os.path.isfile excludes fifos/devices/sockets (no hangs); read(cap+1) bounds huge files.
• No new imports (only os) — no binary/unbound-hook.spec change needed.
• Additive payload — backward compatible with the installed fleet.

Scope notes

• Bash/shell excluded by design — only tools with a discrete file-path field.
• No aggregate per-turn cap (per-file already bounded; the Stop exchange already carries content for Read/Write).

Follow-up (separate, gateway/backend — NOT this repo)

Gateway DLP must redact the new file_content field (not just prompt bodies), otherwise .env/keys read by the agent get stored server-side. Flagged by both /cso and /review as the one real governance item of always-on.

Testing

• All 5 python3 -m py_compile clean.
• Helper block md5-verified identical across all 5 files.
• Behavioral tests pass for: abs/relative+cwd, truncation flag, binary/non-UTF8/missing/directory/permission-denied/None/empty/non-str path skips, write-inline, null-path guard, JSON-serializable output.

🤖 Generated with Claude Code

https://claude.ai/code/session_01GrSjwjtXsfxcBpANpkqQg4