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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description goes beyond that by disclosing the shape of the payload (capacity/booking counts, waitlist, teachers, tags), which is real added context given there is no output schema.

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 tight sentences: the field enumeration first, then the underlying API endpoint. No filler, and the most decision-relevant content is front-loaded.

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 sensibly compensates by listing the returned fields, and the readOnly annotation covers safety. It stops short of noting behavior when the sessionId does not exist or any pagination/expansion options, which would have made 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 coverage is 100% and the single sessionId parameter is documented in the schema itself. The description adds no format, constraint, or sourcing guidance beyond what the schema provides, 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 verb and singular resource ("Fetch one session's detail") and enumerates exactly what the detail contains (times, capacity, booking count, waitlist, teachers, location, stream details, tags). The singular "one session" contrasts naturally with the sibling momence_list_sessions.

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 the required sessionId and the singular scope, but the description never states when to prefer this over momence_list_sessions or momence_list_session_bookings. No prerequisites or exclusions are given, so the agent must infer the routing.

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