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

Goes beyond the destructiveHint annotation by explaining the financial consequence ('changes the job's estimate/invoice total') and, critically, the limitation that it does NOT charge the customer's card — a distinction that prevents a costly misread. The raw POST endpoint adds traceability, though auth and error behavior are unstated.

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, front-loaded with the write classification, then consequence, then input source, then endpoint. Every clause carries information; nothing is padding.

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 an 8-parameter mutation with a fully documented schema and no output schema, the description covers effect, non-effect, and input sourcing adequately. Remaining gaps (permissions needed, behavior on invalid item_id) are minor given the rich schema.

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 primary semantics for quantity, price_per_unit, discount, and details already live in the schema. The description reinforces the item_id provenance, but adds little meaning beyond what the schema states, so the baseline 3 applies.

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 and resource ('add a charge (line item) to a job') with the 'WRITE:' prefix making the operation class explicit. It clarifies the resource taxonomy (product, service, or part) so the agent knows exactly what object is created.

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?

Points the agent to the sibling tool kickserv_list_items for obtaining item_id, which is real routing guidance. It does not, however, state when to prefer this over the note-adding or job-update siblings, so exclusions are only partial.

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