Cancel Order

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

The description goes beyond the annotations by disclosing the exact success return ('plain text "order cancelled"') and error conditions (already filled/cancelled). This is extremely valuable for the agent to anticipate outcomes and is not present in the structured annotations. A 5 would require even more context, like rate limits or prerequisites, but this is already very transparent.

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 a model of conciseness: two sentences that cover purpose, success output, and error conditions without an unnecessary word. Every phrase earns its place, and it's easily scannable by an agent.

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 simple tool with one parameter and no output schema, the description covers the essential contract: what it does, what it returns on success, and when it fails. It could potentially mention the behavior for a non-existent order ID, but given the sibling set (submit_order, replace_order) and the annotations (idempotent, destructive), this is complete enough for an agent to operate 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?

The schema already documents the 'order_id' parameter with 100% coverage, including a helpful description. The tool's description doesn't add any parameter-specific information, but per the rubric, baseline 3 is acceptable since the schema covers it. No extra semantic value is added, so a 3 is appropriate.

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 clearly states the tool's function: 'Cancel an open order by order_id.' This is a specific verb+resource combination that leaves no ambiguity. While it's obvious within the order-management context, it doesn't explicitly differentiate itself from siblings like 'replace_order' or 'submit_order', hence a 4 rather than a 5.

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 phrase 'open order' indicates when to use it, and the error message specifies that it fails for filled/cancelled orders, implying these are cases to avoid. However, it doesn't explicitly state alternatives or provide structured when-to-use/not-to-use guidance. The usage context is inferred but clear enough for a 3.

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