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

Annotations already declare destructiveHint=true and idempotentHint=true; the description adds that filled/canceled/expired orders are effectively no-ops and that an agent key is required. This adds auth and no-op semantics beyond the annotation surface without contradicting them.

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?

Four compact sentences, front-loaded with the action and scope, then conditions, argument source, and auth. Every clause earns its place with no redundancy.

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, single-param tool with no output schema, the description covers action, applicability, auth, and id provenance adequately. Minor gap: it doesn't describe the success response shape, though no output schema is declared.

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 covers the single order_id at 100%, so the baseline is 3. The description earns extra credit by giving provenance ('from get_my_orders'), which tells the agent where to source a valid id rather than just restating the field.

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 (cancel) and resource (order) with explicit scope: only WORKING/unfilled orders on the agent's OWN account. This clearly distinguishes it from siblings like place_order and get_my_orders.

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?

Explains the condition under which the tool acts (working/unfilled orders) and what non-qualifying orders do (return status unchanged), plus points to get_my_orders for the id. It stops short of naming an explicit alternative tool, but the when-to-use context is clear.

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