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

Adds real context beyond the annotations: a non-throwing error contract with a fix-it message, an explicit retry-safety statement, verdict string values, and a PREMIUM/license gate. The license gate is the one soft spot — it flags that something is restricted but never says what happens if the license is absent.

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?

Front-loaded claim, then inputs, then return shape, then usage rule, then error behavior — a deliberate and efficient order with no filler. The inline JSON examples are dense but productive, though the compressed parenthetical style takes slightly more parsing than plain prose would.

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 3-parameter premium tool with a nested optional object, the description covers selection, input shape, return fields, verdict values, and failure/retry behavior. The return-value restatement is partially redundant with the output schema, but it does no harm and leaves no gap an agent would have to guess at.

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 coverage is 100%, so the baseline is 3; the description goes further by showing a typical {original, rewrite} payload and by explaining what the optional fingerprint parameter unlocks ('numeric distance to the target voice'), which the schema only gestures at with a pointer to voice_fingerprint.

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 concrete verb and resource (verify a rewrite) and enumerates the exact outputs (score delta, meaning check, voice distance), which distinguishes it immediately from ai_tell_scan and burstiness_report.

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?

Explicitly names the precondition ('Use only when both the before and the after text are available') and the exclusion with the sibling to use instead ('Not for scoring a single draft (ai_tell_scan)'). Nothing about tool selection is left to inference.

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