get_canister_interface

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

With no annotations, the description carries full burden. It conveys a read-only 'Fetch' operation and implies a non-destructive nature, but does not disclose authentication requirements, error cases, or return format beyond 'Candid interface definition'.

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 two sentences, with the action front-loaded and a succinct usage directive. No filler words; every phrase contributes to clarity.

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 fetch tool with no output schema, the description explains what it does and when to use it. It could be improved by hinting at the response format or any constraints (e.g., that known_type is optional), but the current level is sufficient for a straightforward discovery operation.

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%, with both parameters having descriptive details (e.g., known_type enum/default, canister_id as 'The canister Principal ID'). The description adds no extra parameter-level meaning, so baseline 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 uses a specific verb ('Fetch') and clear resource ('Candid interface definition for a canister'). It also distinguishes itself from sibling call_canister by framing itself as a discovery tool for methods before invocation.

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: 'Use this to discover available methods before using call_canister.' This names the alternative tool and the temporal relationship, making the decision boundary clear.

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