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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral context beyond that: the returned structure (subgoals with ids and done, arrows with after/leads_to, locked) and the non-obvious date behavior for resolving containing periods.

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?

Front-loaded with what is returned, then the horizon qualifier, then the date hint. Dense but every clause (subgoals, arrows, locked, date behavior) carries information; only the parenthetical notation is a bit telegraphic.

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?

There is no output schema, so the description must convey return contents, and it does list the key fields (subgoals, arrows, locked). Safety is covered by annotations. Missing only ordering/pagination/empty-result detail for a zero-required-param list tool.

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 50% (date documented, horizon not), so the description must carry some weight. It clarifies the horizon behavior (all three by default, or one) and explains what date does semantically, which is not derivable from the ISO pattern alone. Adequate but not rich.

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 identifies the resource ('the user's goals') and the scope (month/quarter/year horizons) specifically enough to separate it from sibling readers like get_tasks or list_spheres. It lacks an explicit verb ('List') and does not name any sibling, but the resource and scope are 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?

'Pass date to see the periods that contain another day' and 'or only one horizon' imply when each parameter applies, giving implied usage context. However there is no explicit when-to-use guidance, no when-not-to-use, and no named alternative among the many sibling list_/get_ tools.

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