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

Annotations already declare readOnly/non-destructive, so the burden is lower. The description adds genuinely useful behavior beyond them: results are cached, and an empty chart signals the cache is still building with a retry suggested. It stops short of noting auth scope or failure modes.

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?

Two tight sentences with zero filler; the resource, its scope, and the cache caveat are all front-loaded before the raw endpoint reference.

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 carries the return shape burden and does describe the chart data plus a key edge case (empty chart). It is nearly complete for a single-resource getter, though it omits any note on what a goal object contains or error handling.

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%, and the goal_id description already tells the agent the id comes from wakatime_list_goals. The description adds no further syntax or format detail beyond what the schema provides, so the baseline 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?

States a specific verb and resource: retrieves "One goal by id with its chart data." The "by id" scope cleanly distinguishes it from the sibling wakatime_list_goals, and the included raw path (GET /users/current/goals/{goal}) pins down the exact operation.

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?

Usage is only implied: the tool takes a single goal_id, so the agent infers it is for fetching one known goal rather than listing. It never explicitly says when to prefer this over wakatime_list_goals or what precondition (having a valid id) is required.

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