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

Beyond the annotations, the description discloses important business rules: integer cents, quantity and decimal limits, a maximum line total, refusal of negative prices, and a CONFLICT on converted quotes. These are exactly the behavioral details an agent needs before invoking this non-idempotent mutation.

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?

The definition is dense but well structured: purpose first, then parameter conventions, constraints, refusal cases, and a next step. Every sentence carries operational value, especially given the low schema coverage.

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 eight-parameter create tool with no output schema, the description covers the critical pricing, quantity, tax, and refusal semantics. It is not fully complete because it does not explain quote_id, position, or what a successful response contains beyond directing the agent to quote_read.

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 only 25%, so the description must compensate. It does so strongly for the financially critical fields—unit_price_cents, quantity, discount_bps, unit, and tax_code—but leaves quote_id, position, and description without added semantic guidance.

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?

The description opens with a specific verb and resource: 'Adds one line item to a quote.' It clearly distinguishes this from quote creation and from item list/read/update/delete siblings by emphasizing 'one line item' rather than the quote itself.

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?

It gives explicit usage conditions and alternatives: use discount_bps instead of a negative price, split lines above the ceiling, and change the invoice for a converted quote. It also provides a next step, 'quote_read', making the workflow clear.

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