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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: the record is framed as the buyer's statement, it is later surfaced under inspect_offer thread.purchasing, and it explicitly does not place orders or move money. It does not describe what a successful call returns, but that is minor against the annotation coverage.

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?

Two sentences, front-loaded with the purpose before the enumeration and scope disclaimer. The six-item list is dense but each item corresponds to a real field the caller must supply, so nothing is padding. The middle clause 'Recorded as the buyer's statement' is slightly awkwardly spliced in but still 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?

For a six-parameter, nested-object mutation with no output schema, the description covers purpose, scope boundaries, and where the recorded data is later read. The concurrency guard on terms_sha256 is documented in the schema, so its absence from the description is acceptable. Only the success/response behavior is unaddressed.

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 83%, so the baseline is 3. The description nonetheless adds meaning for the nested requirement fields that the schema leaves bare — vendor_approval_required, purchase_order_required, buyer_vendor_id, and payment_terms_days — by explaining them in plain business terms. Identity and integrity parameters (id, token, terms_sha256, name, organization) are left entirely to the schema, which already documents them.

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 ('Tell the business how the buyer's purchasing works for this offer') and then enumerates exactly which facts are recorded: vendor approval, PO requirement, documents, vendor id, order/invoice route, payment terms. The closing line 'Nothing here orders or pays' separates it from submit_purchase_order, so an agent can pick between them without opening a schema.

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?

Usage context is clear: this is the buyer's statement of purchasing requirements, and the counterpart read is 'the business answers it in inspect_offer thread.purchasing', which tells the agent where the data surfaces afterwards. There are no explicit exclusions or named alternatives (submit_purchase_order is only implied via 'Nothing here orders or pays'), so it falls short of a 5.

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