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

Annotations declare destructiveHint=true, and the description justifies it by disclosing that notes are replaced rather than appended and that only four states are reachable. It stops short of permissions/auth requirements or irreversibility details, but adds meaningful context beyond the annotation.

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 tightly packed sentences: capability first, boundary second, with the GraphQL mutation name as a compact trailing detail. No filler or redundant restatement of the title.

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 3-parameter mutation with no output schema, the description covers what changes, which values are valid, and what is out of scope, which is enough to call it correctly. Minor gaps (no mention of permitted states beyond the enum, no side-effect or return-shape note) keep it from a 5.

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%, so the baseline is 3, but the description adds interpretation the schema lacks, mapping the enum values to real-world intents (CONFIRMED = confirm, ARRIVED/ACTIVE = check the client in). It also reinforces that notes is a full replacement.

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 (update/replace), resource (appointment), the exact fields affected (internal notes and state), and enumerates the target states. It also draws a hard boundary ('Does not cancel or reschedule'), so an agent can distinguish this from other appointment operations 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?

Gives concrete usage context with examples ('confirm, or check the client in') and a clear exclusion for cancel/reschedule. It does not name a sibling alternative, but no cancel/reschedule sibling exists in the sibling list, so the negative guidance is about capability scope rather than tool routing.

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