kin_session_heartbeat

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

Annotations already declare it is not read-only, not idempotent and not destructive, so the safety burden is light. The description adds meaningful behavioral context beyond the annotations: the tool's effect is TTL refresh and the consequence of omission (session lapses), which the structured fields do not convey. It does not specify a recommended interval, which is a minor gap.

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?

Two short sentences, no filler, and the imperative action is front-loaded ahead of the rationale. Every 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 single-parameter keep-alive tool with no output schema and annotations covering the safety profile, the description supplies enough to call it correctly. A recommended cadence would make it fully complete.

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% for the single session_id parameter, so the schema already documents the input. The description adds nothing about the parameter itself (e.g. which session's UUID, defaults), so the baseline 3 applies.

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?

States a specific action ('Keep this session alive') on a specific resource (the session), and clarifies the mechanism (preventing lapse at the idle TTL). An agent can distinguish this from kin_session_start/kin_session_end without opening a schema.

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?

Gives clear invocation timing ('Call it periodically during long work') and the reason (idle TTL lapse). It doesn't explicitly state when not to call it or name a sibling alternative, but the when-to-use condition is unambiguous.

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