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

The description discloses atomic increment semantics, monotonic uniqueness, starting value, and indefinite persistence—details beyond the annotations. These are valuable behavioral traits that the annotations (all false hints) do not convey.

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 sentences, front-loaded with the core action, then use cases and persistence info. No wasted words.

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 counter tool with no output schema, the description covers action, return value, initial state, concurrency, and persistence. The only minor gap is clarification of required vs optional parameters, which the schema already handles.

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 has 100% coverage with descriptions for all parameters, so a baseline of 3 applies. The description mentions 'named counter' but doesn't add further parameter-specific guidance beyond the schema.

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 clearly states the tool atomically increments a named counter and returns the new value, with explicit use cases for sequence numbers and run IDs. It distinguishes from sibling tools by emphasizing atomicity and monotonicity, which is unique among the listed siblings.

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 provides explicit use cases ('use it for sequence numbers, run IDs, or once-only ordering') and context ('across concurrent stateless runs') that indicate when to use it over alternatives. However, it does not name alternative tools or give explicit when-not guidance, so it's not a 5.

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