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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, so safety is covered; the description adds real value beyond that by disclosing the cost ('Free.') and enumerating the verdict semantics ('repeats' at two or more prior pieces, 'builds_on', 'new'). It does not describe latency or failure behavior, keeping it short of a 5.

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-loads the trigger ('Before you write') and then the return shape; every clause carries information. It is dense and long for a two-parameter tool, but no sentence is idle.

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 must explain returns and it does so completely: verdict values, closest prior pieces with quotes, ESTABLISHED ideas, GAPS, and up to three grounded angles. Combined with the usage guidance, an agent has everything needed to call and consume this tool.

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 50%: 'brief' is documented in the schema and the description adds only light framing (the brief/topic you intend to write about, plus that a chosen angle goes in it). 'profile_id' is undocumented in both schema and description. Baseline 3 is appropriate when the schema carries half the load.

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 (check) and resource (a brief against the profile's Voice Brain memory) and immediately distinguishes itself from sibling checks like check_voice_match. An agent knows exactly what this produces: a novelty verdict against prior writing.

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 sequence: 'Before you write... Use it before generate_content: put the chosen angle into the brief.' It states when to call it and what to do with the result, which is stronger guidance than most siblings provide.

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