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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description goes beyond them by disclosing pagination behavior ('50 by default and 100 at most, with a flag when more exist') and the fact that returned identifiers are needed to select a project, which is real operational context.

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 tight sentences with no filler, and the trigger condition is front-loaded before the scope, payload, and pagination details. Every clause carries information an agent needs.

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 simple read-only list tool with an output schema present, the description covers the trigger, the exclusion, the scoping to the connected account, and the pagination ceiling. Nothing required to call it correctly 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?

There is one optional parameter with 100% schema description coverage, so the schema already documents the 1–100 range and the 50 default. The description restates those bounds without adding format or interaction detail, so baseline 3 is appropriate.

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 verb and resource ('list projects accessible to the connected CronCool account') and states the scope constraint (account-bound, not global). The closing clause 'Not for listing jobs' explicitly differentiates it from the sibling list_jobs, so an agent can route without opening a schema.

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?

It gives a clear trigger ('Use this when the user wants to list projects') plus an explicit exclusion ('Not for listing jobs'), covering when-to-use and when-not. It stops short of naming the sibling to use instead (list_jobs), which is the only thing separating this from a 5.

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