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

Adds substantial context beyond the annotations: idempotency semantics (same key returns same order, never a second), server-side re-pricing and refusal, and payment branching (payment_url for card, none for on-account, held for Team owner). These are non-obvious behaviors an agent must anticipate.

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?

Dense but front-loaded: purpose first, then idempotency, then failure handling, then payment outcomes, then auth. Every sentence carries operational meaning, though the auth sentence could be tightened.

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 destructive, open-world mutation with an output schema, the description covers permissions, idempotency, failure recovery, and payment outcomes. Nothing an agent needs before invoking it 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 parameters are documented; the description still adds value by explaining that confirmation_token comes from prepare_checkout and that idempotency_key must be a newly generated UUID reused only for retries. Slightly redundant with the schema's own descriptions, hence not a 5.

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 ('Places the order prepare_checkout summarised') and ties it directly to the sibling that precedes it. An agent can distinguish it from prepare_checkout, approve_order, and convert_quote_to_order from the text alone.

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?

Explicit preconditions ('after the customer has seen that summary and said yes', 'Never call it without the customer's agreement') and a recovery path ('refuses a price that moved... then call prepare_checkout again'). Also disambiguates payment responsibility by order type.

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