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

Annotations already declare readOnly=false, idempotent=true, destructive=false. The description adds valuable context beyond these: partial update semantics (only passed fields change) and the explicit non-mutating boundary regarding meeting time. This enriches the behavioral model without contradicting annotations.

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?

The description is three sentences, front-loaded with the primary purpose, followed by a usage context and a clear distinction from a sibling tool. Every sentence earns its place with no redundancy or fluff.

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 mutation tool with no output schema, the description provides what an agent needs: what it does, when to use it, partial update behavior, and which sibling handles related cases. The annotations cover safety/idempotency, making this sufficient for correct selection and invocation.

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 high at 83%, so the baseline is 3. The description adds meaning by grouping topic, desired_outcome, and background under the concept of 'the brief' and by clarifying that only provided fields are changed, which is not fully explicit in the schema. The order_id parameter lacks description in the schema and the description does not compensate, but it is a standard required identifier.

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 uses a specific verb ('Change') and identifies the precise resource ('session type or the brief on an existing booking'). It further clarifies scope by naming the fields involved (what to discuss, desired outcome, background) and explicitly differentiates from reschedule_booking by stating it does not move the meeting.

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 explicitly states when to use the tool: 'when the buyer refines their thinking after booking.' It also provides a clear exclusion and alternative: 'This does not move the meeting — use reschedule_booking for that.' Additionally, it explains the partial update behavior ('Only the fields you pass are changed'), guiding proper invocation.

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