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

The description says the tool 'Book[s]' a session, which is a scheduling/side-effecting action, while annotations declare readOnlyHint=true (no side effects) and openWorldHint=false (no external interaction) — yet the session is explicitly with an external party, 'Legal HQ'. The description contradicts both hints, and the boilerplate has no other behavioral disclosure to fall back on.

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?

A single well-formed sentence with the action and object front-loaded and no filler. It is appropriately sized for a zero-parameter tool, though the 'get' vs 'book' mismatch slightly muddies the lead.

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?

There is no output schema, no parameters, and no annotations beyond the safety hints, so the description carries the burden — yet it never says what the tool returns or how the booking is actually effected (link, confirmation, calendar invite). For a simple zero-param tool this is minimally viable, but the contradiction with annotations leaves the agent guessing.

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?

The tool takes zero parameters, so there is nothing for the description to clarify; baseline 4 applies. The description does not need to compensate for any schema gap.

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 names a specific verb ('Book') and resource ('one-hour setup session with Legal HQ'), but it conflicts with the tool name get_setup_session, which implies retrieval rather than booking. An agent cannot tell whether this schedules a session or returns information about booking one. Purpose is therefore recognizable but genuinely ambiguous.

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?

It states the session is paid and what it covers, but gives no guidance on when to invoke it versus the listed siblings (get_case_prep_checklist, get_starter_kit, about_legal_hq), nor any prerequisites or exclusions. The mention of 'paid' is a fact, not routing guidance.

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