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

The annotation readOnlyHint=true already covers the safety profile (read-only). The description adds only the REST endpoint path, which does not disclose additional behavioral traits such as what happens if the id is not found, rate limits, or permission requirements. It does not contradict annotations, but it also goes little beyond them.

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 description is two sentences, each earning its place. The first sentence states the verb and resource; the second gives the REST endpoint for reference. There is no fluff or redundant phrasing.

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?

Given the simple tool (one required parameter, no output schema) and the readOnlyHint annotation, the description is sufficient. It explains what the tool does and the id parameter is fully documented in the schema. It does not explain return values, but for a simple retrieval tool this is acceptable without an output schema.

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 input schema has 100% description coverage for the single parameter (time_entry_id is described as 'The time entry id (required).'). The tool description does not mention the parameter or add extra meaning beyond what the schema already provides, so the baseline score of 3 is 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?

The description clearly states a specific action ('Retrieve a single time entry by id') and the resource (time entry). It distinguishes from sibling tools like harvest_list_time_entries (plural) and mutation tools (create/update/delete) by emphasizing 'single' and 'by id'.

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 implies the use case: when you have a specific time_entry_id and need that one entry. It does not explicitly name alternatives (e.g., 'use list_time_entries for multiple entries'), but the context is clear enough that an agent would know when to invoke it. This is 'clear context, no exclusions'.

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