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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the REST provenance (GET /api/assist/habits/daily/{id}), which helps agents correlate with the API, but says nothing about error behavior when the id is unknown or what the returned habit contains.

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 short sentences, front-loaded with the purpose before the API mapping. Nothing is padded, though the bare REST path is of marginal use to an agent and is the only content after the core statement.

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 simple single-parameter read tool whose annotations cover safety, this is nearly adequate. However, with no output schema, the description could have described the shape of the returned habit, and it offers no guidance on missing/unknown ids.

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% and there is a single required parameter, so the schema already documents 'id' fully. The description adds no format, sourcing, or constraint detail beyond what the schema states, making the baseline 3 appropriate.

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 ("Get a single daily habit by id") and the singular scope implicitly distinguishes it from the sibling reclaim_list_habits. No sibling tool is named, so differentiation rests on inference rather than explicit contrast.

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?

The description never says when to use this tool versus reclaim_list_habits, nor does it state prerequisites such as needing a previously obtained habit id. Only the phrase "by id" hints at the required context; there is no explicit when-to-use or exclusion guidance.

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