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

Annotations already carry destructiveHint=true, and the 'MUTATING' label reinforces rather than contradicts that. The description adds the Zendesk REST endpoint (PUT /tickets/{id}.json), but says nothing about reversibility, permission requirements, or what happens to fields omitted from the payload — a meaningful gap for a destructive write tool.

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 compact sentences: the mutating nature is front-loaded, the required-input rule follows, and the REST endpoint anchors the call. No sentence is filler.

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 9 mostly-optional parameters at full schema coverage and a destructiveHint annotation, the description covers the essentials: the required id, the at-least-one-field rule, and the mutation semantics. It omits return-value expectations (no output schema exists) and the partial-update behavior of omitted fields, so it is strong but not 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 description coverage is 100%, so every parameter including the comment_public default is already documented in the schema. The description's field list slightly overlaps the schema but adds no syntax, format, or interaction guidance beyond it, making the baseline 3 appropriate.

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?

Names a specific verb and resource ('update an existing ticket') and prefixes it with 'MUTATING', which cleanly separates it from the read siblings (zendesk_get_ticket) and from zendesk_create_ticket. The enumeration of updatable fields makes the scope concrete rather than tautological.

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?

States a clear precondition ('Provide the ticket id plus at least one field to change') and lists the acceptable fields, which tells the agent how to form a valid call. It does not, however, tell the agent when to prefer a sibling such as zendesk_add_ticket_comment or when not to use this tool.

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