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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered. The description adds useful behavior: it defaults to tomorrow and describes the aggregated content returned, which the annotations do not convey. No output schema exists, so this enumeration carries real weight.

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?

Three compact sentences, front-loaded with the payload contents, then the default, then the workflow routing. Every sentence 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 single-optional-param, read-only tool, the description lists the returned context and the default date, compensating for the absent output schema. Coverage is nearly complete, though it doesn't state the response format or the date-selection effect on the aggregate windows.

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%, so format (YYYY-MM-DD, user timezone) is already documented. The description adds the default behavior ('Defaults to tomorrow'), which is meaningful semantics not present in the schema, exceeding the baseline 3.

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 resource (a bundle of planning context) and enumerates its contents: goal and pace, next_steps, yesterday's summary and undone items, week balance, days since a hard lever. It also distinguishes its role from siblings by noting the agent plans and then calls set_plan rather than get_plan/next_steps.

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?

Clearly positions this as the first step of a planning workflow and names the follow-up tool (set_plan), which is strong context. It lacks explicit 'when not to use' exclusions (e.g., versus get_plan or next_steps), so it stops short of the top score.

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