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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the description's "Read-only" line adds nothing. The added value is elsewhere: the empty-result semantics for goals the caller doesn't own (no error raised) and the presence of goal_progress_pct in the result, which are non-obvious behaviors the annotations do not convey.

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?

Four short sentences, front-loaded with what the tool returns and how to call it, followed by the progress-signal purpose. The one wasteful element is "Read-only.", which merely repeats the readOnlyHint annotation.

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?

With no output schema, the description does well to surface goal_progress_pct and the ordering of milestones, and it sets the correct expectation for foreign goals. It still omits any description of the milestone objects themselves (identifiers, done state, position fields) and the undocumented 'limit' parameter, so the picture is not fully complete.

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 0%, so the description carries the burden, and it only partly discharges it. It explains goal_id and done, but the 'limit' parameter (1-100) is never mentioned in the description or the schema, leaving one of three parameters fully undocumented. The loose integer|string typing of goal_id is also unaddressed.

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 gives a specific verb and resource (list the checkable milestones of a goal), plus scope ordering ("in position order") and ownership scoping ("one of the caller's goals"). That is enough for an agent to distinguish it from goals_list, which operates one level up on the goals themselves.

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 the required input ("Provide 'goal_id'") and the optional narrowing filter ("optionally filter by 'done'"), which is clear invocation guidance. It also explains what a non-owned goal yields, so the agent knows this is not an error path. It stops short of naming an alternative tool or an explicit when-not-to-use condition.

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