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

With no annotations, the description carries the full burden. It conveys that this is a read-only status check scoped to 'today' and a 'daily limit' rather than a mutation, but it does not say whether the limit is hard or soft, what happens when exceeded, or what form the result takes (count, percentage, remaining quota).

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?

A single sentence, front-loaded with the verb and object, with no filler. Every word carries meaning and nothing is repeated from structured fields.

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 zero-parameter read tool with no output schema, the description covers what the agent needs to decide to call it. The one remaining gap is the response shape, which matters somewhat since no output schema exists to fill it in.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline applies. The description correctly signals that the scope is implicit rather than parameterized.

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?

Specific verb 'Check' plus a clearly scoped resource: today's transcription usage measured against the plan's daily limit. It is readily distinguishable from the sibling transcribe_audio by resource, though it does not name that sibling explicitly.

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 phrase 'against your plan's daily limit' implies the use case (quota checking before or after transcribing), but there is no explicit when-to-use statement, no prerequisite, and no reference to transcribe_audio as the alternative action.

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