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

Beyond the annotations (which only say it is a non-read-only, non-destructive, non-open-world write), it discloses key behavioral traits: the concurrency guarantee ('two agents asking at once never get the same number'), the overlap with hook-driven auto-claiming, and the return format ('zero-padded like the files already there'). This is exactly the kind of context annotations cannot provide.

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, tightly packed, with the core action front-loaded and the caveat/exception following immediately. Every clause carries information the agent needs; nothing is padding.

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 compensates by describing the return value (the zero-padded number). Combined with the concurrency guarantee and the hook-overlap warning, an agent has everything needed to call this correctly, and the 4-param schema is fully self-documented.

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 description coverage is 100%, so all four parameters are already documented in the schema, which sets the baseline at 3. The description's mention of 'a named sequence' versus numbered directories loosely mirrors the sequence parameter's dual meaning, but adds no syntax, format, or default information 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 states a precise verb+resource ('Reserve the next number in a sequence') and enumerates concrete sequence kinds (a migration, an ADR, a release), so the agent knows exactly what operation this performs. No sibling tool (declare_intent, remember, recall, etc.) overlaps with this behavior, so there is no ambiguity to disambiguate against.

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 both a when-to-use and an explicit when-not-to-use: the hooks already claim a numbered file's number on creation, so only call this 'for a number you need before writing, or for a named sequence.' That is an unusually clear routing rule for an agent deciding between this and simply creating the file.

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