report_liveness

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations were provided, so the description carries the full burden. It thoroughly discloses behavior: updates agent_pid + agent_pid_start and fills host_id when NULL, does NOT rotate session_id, does not bump last_seen or touch read cursor, is idempotent, and requires own agent token only. Returns and errors are documented.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-organized with labeled sections (When to use, Behavior, Returns, Errors) and is front-loaded with the core purpose. It could be mildly trimmed—the Returns/Errors sections are partly visible in schema contexts—but each sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple metadata-only self-report with 100% schema coverage and no output schema, the description is remarkably complete. It covers when to use, behavior, idempotency, auth requirements, return shape, and error cases—more than sufficient for correct invocation and expectations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all 4 parameters thoroughly. The description adds context about liveness semantics (restamping same values is a no-op, PID-liveness only when start-time is null) which enriches the parameter meaning beyond what schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb+resource ('Restamp your own liveness anchor — agent_pid + process start-time') with a narrow, well-scoped metadata-only self-report. It clearly distinguishes this from siblings like register_agent by explicitly noting it rotates session_id while this does not.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit 'When to use' section explains that hooks call this automatically, and contrasts it directly with register_agent which rotates session_id and can re-surface already-read mail. Also states 'You rarely call it by hand', giving clear when-to/not-to guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.