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

Annotations supply destructiveHint=true, and the description adds genuinely useful context beyond that: the operation is a PATCH-style partial update (unspecified fields are preserved) and it targets an existing resource identified by UUID. It still omits auth/permission requirements and the failure mode when the UUID does not exist.

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?

Three tight sentences: purpose first, then the wire format. Every clause carries information (partial semantics, endpoint template, body shape) and nothing is repeated or padded.

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 five-parameter mutation tool with no output schema, the description covers the operation, identifier scheme, endpoint, and payload structure adequately. It leaves error handling and permission requirements unstated, but nothing essential for a correct call is missing.

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. The description goes beyond the schema by documenting the request envelope { data: { type, id, attributes?, relationships? } }, which reveals the required type/id wrapper fields the schema does not mention directly.

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+resource ("Update an existing resource by UUID") and scopes it precisely as a partial update of attributes and/or relationships, plus the exact JSON:API endpoint. It does not name a sibling tool, so the agent must infer the create/delete boundary from the verb, which keeps it just short of a 5.

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 rather than stated: "partial update" and "existing resource" signal when this is appropriate versus create/delete, but there is no explicit when-to-use, when-not-to-use, or named alternative among the sibling tools.

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