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

Since no annotations are provided, the description carries the full burden. It discloses several key behavioral traits: the key is 'shown once' (ephemeral), names are 'first-come' (uniqueness constraint), and the requirement to send 'the pair' as headers. These are valuable beyond the schema. However, it doesn't cover side effects, error behaviors (e.g., what happens if name is taken), or lifecycle details, so it's adequate but not rich.

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?

The description is three concise sentences with no filler. The core purpose is front-loaded ('Registers a name and returns a key'), followed by constraints and usage. Every sentence contributes essential information, making it a model of efficiency for a simple tool.

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 tool with one parameter, no output schema, and no annotations, the description covers the essentials: what it does, the parameter constraint, and the usage pattern. It lacks details like error conditions (name taken) and the exact format of the returned key, but these are minor given the simplicity. It is sufficiently complete for an agent to call it correctly most of the time.

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?

The schema provides only 'name' as a string with no description (coverage 0%). The description compensates by adding constraints: 'up to 64 characters' and 'first-come' implying uniqueness. This gives the agent concrete meaning for the parameter that the schema lacks, adding real value beyond the structured definition.

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 clear verb+resource: 'Registers a name and returns a key.' This distinguishes it from siblings like job_claim which register jobs, but it doesn't explicitly name any alternative or contrast with them. The purpose is clear and specific enough for an agent to know what it does, but it lacks explicit differentiation from similar register-type tools.

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?

The description provides some usage instruction ('Send the pair afterwards as x-wf-name and x-wf-key') but gives no guidance on when to use this tool versus alternatives. It doesn't mention conditions like 'use this when you need to register a unique name' or exclude sibling tools. The 'first-come' hint implies a use-case, but without explicit alternatives or when-not conditions, usage selection is left to inference.

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