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

Annotations already declare readOnly, non-destructive, idempotent, and closed-world behavior, so safety is covered. The description adds value beyond them: the result ordering, the inside/outside Mador classification, and especially the plan gating that changes behavior (Growth plan only). It omits return format/pagination detail, but that is minor for a simple list.

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?

A single compact sentence that front-loads the resource and scope, with the ordering and plan caveat following. It is efficient overall, though the inside/outside Mador clause is slightly padded and could be implicit in the results.

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, single-parameter list tool with no output schema, the description covers what is returned (open to-dos, ordered, with inside/outside classification) and the plan-gating behavior. It is largely self-sufficient; only edge cases like empty results or scope of 'this week' are left undefined.

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 project_id parameter is already fully documented, including its optionality when the account has one project. The description only implicitly references 'this project' and adds no syntax or format detail beyond the schema, so the baseline of 3 applies.

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 names the specific resource (open to-dos Mador suggests for this project this week), the ordering (most useful first), and an extra dimension (done inside or outside Mador). It is clear and specific, but it never explicitly distinguishes itself from siblings — though the resource itself (to-dos vs competitors/mentions/pages/questions/status) is inherently unambiguous.

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?

It states a real usage constraint — 'Growth plan only; on other plans it says so' — which tells the agent the tool behaves differently by plan. However, there is no guidance on when to prefer this over alternatives or any prerequisites for the call itself; usage is implied by the resource rather than spelled out.

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