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

With no annotations, the description carries the full burden and does well: it discloses cost ('Free'), freshness guarantees ('generated from the same registry the paid endpoint validates against, so it is never stale'), and the shape of what comes back. It doesn't state read-only semantics explicitly, but 'catalog' and 'Free' strongly imply it.

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?

Three short sentences, front-loaded with the cost signal and the 'call this first' directive, then the trust signal. No 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?

For a zero-param, output-schema-less list tool, the description covers what makes a caller act: what's returned, that it costs nothing, that it's authoritative and fresh, and that it should be called before the paid tools. Nothing an agent needs is missing.

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?

Zero parameters, so there is nothing to disambiguate; baseline 4 applies. The description correctly spends no words on inputs.

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 resource and its exact contents: 7 growth coaches, the 16 modes they sell, and each mode's price. The word 'catalog' plus the concrete counts makes it unmistakable next to siblings like call_coach or list_actions.

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?

'Call this first' gives explicit ordering guidance, and 'Free' versus 'the paid endpoint' frames the cost tradeoff against call_coach. It stops short of naming the sibling tools or stating when not to call it, so it lands just under a 5.

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