canvas_modules

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the returned field set (ids, names, lock or completion state), which matters because there is no output schema. It does not discuss pagination behavior, though the schema documents the page parameter.

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, zero filler, and the core purpose is front-loaded before the follow-up hint. The parenthetical definition of a module is the only non-essential content and it earns its place by orienting an agent unfamiliar with LMS structures.

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 read-only three-parameter list tool with full schema coverage and no output schema, the description covers purpose, returned fields, and the natural follow-up call. Only pagination behavior and the singular-vs-list distinction are left implicit, both minor given the schema documents the page token.

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 100%: course_id, page, and raw are each documented in-schema, including the next_page pattern for pagination. The description adds no param-level detail beyond pointing at course_id indirectly and mentioning module_id, which is not a parameter here. Baseline 3 applies when the schema does the heavy lifting.

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?

Specific verb+resource ("List a course's modules") plus a parenthetical defining what a module is in this domain, and it names the fields returned (ids, names, lock or completion state). An agent can distinguish this from canvas_module (single) and canvas_module_items (contents) 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?

The second sentence gives explicit routing guidance: use the returned module_id with canvas_module_items to see contents. That is a clear next-step condition. It does not state when to prefer canvas_module for a single module or when not to fetch modules at all, so it falls short of full when/when-not coverage.

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