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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, and the description still adds real behavioral detail beyond them: fail-closed handling of conflicting, future or invalid events, the not_attested state of runningNow, and the explicit distinction between unknown, unavailable and canceled. This tells the agent how to interpret and trust the result, which the annotations cannot.

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 purpose is front-loaded in the first sentence, and the four following sentences each carry distinct information (trust caveat, failure mode, status taxonomy, non-capabilities). It is dense and slightly jargon-heavy ('runningNow remains not_attested') but free of filler.

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 does the work of describing the payload (status plus event time/source/age) and the status taxonomy, which is substantial. The gap is what 'fail closed' actually returns to the caller — an error, an empty result, or a status value — which an agent would want before calling.

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?

Only one parameter exists and schema description coverage is 0%, so the description carries the burden; it does add that the reservation is tenant-scoped, implying isolation of the ID. But it says nothing about the reservationId's format, expected length, or what an unknown ID produces, leaving the single parameter under-specified.

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 names a specific verb and resource with scope: 'Read one tenant-scoped reservation and its last recorded chauffeur status,' and enumerates the returned fields (event time/source/age). That is enough to separate it from list_rides and the other get_* siblings, though it never explicitly contrasts itself with them.

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 context is clear: this is for inspecting a single already-identified reservation's last recorded status, not live tracking ('not real-time GPS or current-driver proof'). It also closes off adjacent intents ('No writes, dispatch, messages or provider calls'). It stops short of naming an alternative tool to use for real-time or dispatch needs.

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