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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), yet the description still adds real behavioral context beyond them: the trail is recorded only while the driver is on the job, is retained for 30 days, and access depends on whether the caller is internal staff or a partner/customer. Retention window and recording conditions are exactly the kind of operational detail annotations cannot express.

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 sentences, front-loaded with what the tool returns and immediately followed by when to use it and the access constraint. The parenthetical gloss on 'breadcrumb trail' earns its place by disambiguating jargon; nothing is padding.

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 itself (the driven path plus a distance/duration summary) and adds retention and authorization constraints. For a two-parameter read tool with annotations, an agent has everything needed to call it correctly.

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%, so both parameters are already documented, and the description's restatement of the email-vs-numeric-ID rule largely mirrors the schema text. It confirms rather than extends parameter meaning, which is the baseline-3 case when the schema does the heavy lifting.

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 with unusual precision: the driver's recorded GPS route as a breadcrumb trail for a booking's trip, plus a distance/duration summary. The word 'recorded' implicitly separates it from the live sibling track_driver, but no sibling is named explicitly, so it stops short of the top score.

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?

Gives two concrete use cases ('route playback', 'verify a driver attended'), which is clear context for when to reach for it. It offers no when-not guidance and does not name track_driver as the alternative for live position, so an agent must infer the boundary itself.

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