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

Adds real context beyond the thin annotations (only destructiveHint): the write nature, that no notification is sent to the customer, and that trashing is unsupported. It does not state whether omitted fields are preserved or replaced (a significant nuance for a PUT-style update) or what permissions are required, which keeps it short of a 5.

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?

Front-loads the WRITE classification and keeps the payload-detail sentences tight; the raw endpoint reference (PUT /api/v1/cases/{id}.json) is defensible for traceability but is slightly redundant overhead.

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 12-parameter mutation with no output schema and sparse schema descriptions, the description covers the field surface, the no-notification behavior, and the excluded destructive operation. The main remaining gap is the partial-vs-full update semantics, which an agent would need to call this safely.

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?

With only 25% schema description coverage, the description carries the load by naming every updatable field group (subject, requester, assignee, status, priority, type, brand, form, tags, custom fields) and clarifying that `tags` sets rather than appends the list. It leaves some ambiguity about assignee team/agent exclusivity and does not detail field_values, but it substantially compensates for the schema gap.

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?

Opens with a specific verb and resource ("WRITE: change a case's ...") and enumerates the exact mutable fields, which lets an agent map intent to tool without opening the schema. It also differentiates itself from the sibling kayako_add_case_tags and from reply-type tools via "Sends nothing to the customer."

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?

Explicitly routes the append case to the alternative: "use kayako_add_case_tags to append," and rules out an unsupported operation ("Trashing is deliberately not exposed"). It also implicitly excludes customer-facing replies by stating nothing is sent to the customer.

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