Update Checkout Session

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

With no annotations provided, the description carries the full burden and does well: it discloses the mutation effect (attaching addresses), the conditional shipping fallback, and the resulting session status 'ready_for_complete'. It could go further by clarifying whether existing addresses are replaced or appended, but it discloses the key behavioral contract concisely.

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 description is well-structured: a one-line purpose, a short usage paragraph, a compact Args block, and a Returns line. There is no filler or redundant restatement of the tool name, and every sentence earns its place.

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?

The description is complete for a mutation tool with zero annotations and no parameter docs in the schema. It covers workflow ordering, required parameters, optional parameters, key structures, defaults, fallback behavior, and expected return status, leaving no critical gap for an agent trying to invoke it correctly.

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 0%, so the schema offers no parameter guidance. The description compensates fully by explaining the source of session_id, listing the valid keys for billing, documenting country default and optional state, and specifying shipping as optional with the same key structure.

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-resource pair – 'Attach billing and shipping address to a checkout session' – and distinguishes it from related siblings by placing it in the sequence between create_checkout_session and complete_checkout. An agent can immediately identify what this tool does and why it is not create, complete, or cancel.

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?

The description explicitly states when to use it ('after create_checkout_session'), identifies it as 'Required before calling complete_checkout', and explains the fallback behavior when shipping is omitted. This gives clear selection guidance without ambiguity.

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