list_habits

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

Annotations already cover readOnlyHint=true, so the read-only nature is established. The description adds value beyond that by disclosing the auth requirement (Full Access Token) and the behavioral trap of the non-raw endpoint. It doesn't describe the response shape, but the output schema exists to cover that, and no contradiction with annotations is present.

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?

The first two sentences are redundant — 'Get all habits with title, settings and history' and 'Get all habits as full documents incl. title, settings and history' repeat the same content before adding the format detail. The crucial warning is well-placed at the end, but the opening duplication wastes space.

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 zero-parameter read tool with an output schema, the description is nearly complete: it covers the auth prerequisite and the critical pitfall distinguishing it from the non-raw endpoint. The only minor omission is an explicit statement of returned fields beyond the history array, but the output schema carries that burden.

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?

The tool takes zero parameters, so the baseline is 4 and the schema is trivially 100% covered. The description compensates by clarifying the return format of the history field ([time1, value1, time2, value2, ...] in unix ms), which informs an agent what to expect without any params to document.

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 states a precise action ('Get all habits') and explicitly enumerates the returned contents (title, settings, history with time/value pairs). The resource and scope are unambiguous, and it separates a bulk listing from the singular get_habit in the sibling set.

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 gives explicit, live-verified guidance: this tool requires the Full Access Token (raw variant of /habits) and explicitly warns that the non-raw variant is wrong here, explaining why (lazy tracking registry, missing never-recorded habits, no titles). That directly tells an agent when and how this tool must be invoked versus its alternate.

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