worker_heartbeat

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

With no annotations, the description carries the full behavioral burden and it does real work: it states the side effect (lease extension) and the failure mode (silence to claims expire to work picked up). It stops short of detailing idempotency or what a successful response looks like, but the core runtime semantics are disclosed.

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?

Three sentences, each with a distinct job: action, consequence, and cadence. The most decision-relevant information is front-loaded and there is no filler.

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?

The description captures why and when to heartbeat and the consequence of silence, which is the minimum viable context. It is incomplete for a 5-parameter/no-output-schema tool because it never explains the optional parameters, the required worker value, or the response/error behavior.

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 coverage is only 20% (only cwd has a schema description), and the tool description compensates for almost none of that. It adds only the general idea that `worker` identifies the living worker; `goal`, `worktree`, and `session_id` remain unexplained and ambiguous.

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 opens with a specific action ('Report that a worker is alive and extend its leases') and names the resource and effect. The stale-silence explanation differentiates it from one-shot status/list tools like worker_list and checkpoint, so an agent can identify its purpose without reading schemas.

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?

'Call this every few minutes while working' is a direct, explicit trigger condition. It does not name alternative tools or give a when-not-to-call exclusion, but it clearly scopes use to active work sessions.

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