Get my planner / upcoming items

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds useful behavioral context: the default date range (yesterday..+14 days) and that this is the unified 'what's due/new' feed. This goes beyond the structured metadata, though it doesn't cover pagination or return format, which are not critical given the annotations.

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 three sentences, each contributing distinct information: what it returns, the default date window, and its unified nature. There is no fluff, and the most important info (resource type) is front-loaded. Efficient and well-structured.

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 planner feed with two optional date parameters and no output schema, the description is reasonably complete. It specifies the item types and the default window. It doesn't detail the output structure, but since there is no output schema and the tool is straightforward, this is acceptable. The title clarifies it's 'my' planner. Minor gap: it could mention that only the current user's items are returned, but the title implies that.

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%, so the baseline is 3. The description adds value by explaining the default behavior when startDate/endDate are omitted, which is not present in the schema. This helps the agent understand that the parameters are optional and that a default window applies, enhancing the parameter semantics beyond the schema.

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 returns 'Planner items (assignments, quizzes, events) in a date window' and positions it as Canvas's unified feed. This is a specific verb-resource pairing with a defined scope. It doesn't explicitly name sibling tools for differentiation, but the 'unified' qualifier helps separate it from single-type tools like calendar_events or todo.

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 implies usage by explaining the default date window and the unified nature, but it does not explicitly say when to prefer this over siblings like canvas_get_todo or canvas_get_activity_stream. No exclusions or alternatives are mentioned, leaving the agent to infer when this is the right choice. This is adequate but not explicit.

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