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

Annotations already declare readOnlyHint=false and idempotentHint=false, so the mutation and non-idempotency profile is known. The description adds that a slot is reserved and a URL returned, but says nothing about how long the reservation lives, whether abandoning it leaks state, or that a follow-up confirm step is required — which matters most for a non-idempotent booking operation.

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 with the primary effect (reserve slot, get URL) front-loaded and the caller restriction second. No filler and nothing to trim.

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?

An output schema exists so return payload explanation isn't required. However, for a non-idempotent write tool with three fully undocumented parameters, the definition omits the lifecycle context (reservation expiry, required follow-up call) an agent needs to use it safely.

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?

All three required parameters have 0% schema description coverage, so the description must compensate and does not — deviceToken, questionId, and mimeType are never mentioned. An agent gets no hint that questionId should correspond to an existing practice question or what the device token represents, leaving it to infer from the UUID formats and the mimeType enum.

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 action and outcome — reserve a recording slot and receive an upload URL — which is clearly distinct from siblings recorder_confirm and recorder_result. It doesn't explicitly contrast with those siblings, but the verb+resource pairing is unambiguous.

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?

"Called by the speaking recorder card only" is a real usage restriction that tells the agent this is a narrow, UI-driven entry point rather than a general tool. It stops short of naming the alternative tools or describing the start/confirm ordering, so the when-to-use guidance is implied rather than spelled out.

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