heartbeat

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

With no annotations provided, the description fully carries the burden of behavioral transparency. It explains the zombie reset sweep, lease extension mechanism, return value semantics (ok vs stale_claim), and the consequence of a stale claim. This exceeds expectations for a heartbeat tool.

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-structured with a lead sentence, followed by paragraphs on zombie reset, lease renewal, and return values. While slightly verbose, every sentence adds value. Minor trimming could improve conciseness, but current structure is effective.

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?

Given the tool's complexity (leases, zombie reset, claim management) and that an output schema exists, the description covers all necessary aspects: calling frequency, parameter defaults, return behavior, and error handling. It is self-contained and actionable.

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 0%, so the description must compensate. It explains step_id can be inferred from $SORTIE_STEP_ID and provides the default for extend_leases_sec (900) along with its purpose. This adds essential meaning beyond the raw schema.

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 'Report that you're still alive and keep your claim + leases fresh,' which is a specific verb-resource pair. It clearly defines the tool's role for long-running agents and distinguishes itself from siblings like complete_step or fail_step by focusing on liveness and lease renewal.

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?

The description states that 'Long-running agents should call this every few minutes,' providing clear timing guidance. It also instructs to 'Stop working immediately' upon receiving a stale_claim response. While it doesn't explicitly exclude other tools, the unique purpose of heartbeat makes alternative uses obvious.

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