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

With no annotations, the description carries full burden. It reveals the tool returns active participants but fails to disclose side effects, read safety, authentication requirements, or any billing implications. The minimal text leaves behavioral traits largely unknown.

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 sentences, no filler, and front-loaded with the core concept. However, extreme brevity sacrifices useful detail, so not a perfect 5. It earns its keep but could be more informative without increasing length significantly.

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 heartbeat tool with an output schema, the description covers the basic return value but lacks parameter details and usage context. It is minimally viable but leaves gaps that could mislead an agent, especially regarding when and how to call.

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 only 33% (only npub described), well below 50%, so the description must compensate. It adds no parameter information whatsoever. The undocumented dpop_token and session_id parameters remain opaque, severely hindering correct invocation.

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 clearly states 'Presence heartbeat. Returns who else is active in this session,' using specific verb 'Returns' and defined resource 'active participants'. It distinguishes from siblings like taxsort_session_status and taxsort_create_session by focusing on heartbeat functionality.

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?

No guidance is provided on when to use this tool versus alternatives (e.g., taxsort_session_status). The context of periodic calling is implied by 'heartbeat' but not explicit, and there are no when-not-to-use or prerequisite instructions.

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