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

readOnlyHint=true already covers the safety profile, so the description's added value is the field-level inventory (times, capacity, booking count, waitlist, teachers, location, stream details, tags). It does not discuss behavior on a missing/invalid sessionId or any permission requirements, keeping it short of a 5.

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?

One dense sentence front-loads the purpose and payload, followed by a compact API reference. No filler and nothing buried.

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?

With no output schema, the description usefully enumerates the returned fields, which compensates for the missing return documentation. For a single-parameter read operation, nothing essential is missing, though error cases are unspecified.

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% with a single documented sessionId parameter, so the baseline is 3. The description only echoes the id in the URL template (GET /api/v2/host/sessions/{sessionId}) and adds no format or constraint meaning beyond the 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?

States a specific verb and resource ('Fetch one session's detail') and enumerates the returned surface area, which cleanly distinguishes it from the plural sibling momence_list_sessions. An agent can pick it without opening the 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?

Usage is implied by 'one session' versus the list sibling, but there is no explicit when-to-use/when-not guidance and no named alternative. Adequate but leaves routing inference to the agent.

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