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

Annotations only declare this is a non-read-only, non-destructive, non-open-world operation. The description adds high-value behavior the agent cannot get elsewhere: the api_token is returned and shown only once, must be stored, and is consumed as an 'Authorization: Bearer' header. This one-time-secret and credential-handling disclosure is exactly the kind of context annotations cannot express.

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?

Two sentences, front-loaded with the action and followed immediately by the critical return-value and auth instructions. No filler; every clause carries operational weight.

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 correctly takes on the burden of explaining the return value (api_token) and how to use it, which is the key thing an agent needs. Minor gaps remain (e.g. whether re-invocation issues a new token, idempotency), but for a single-optional-param signup tool it is nearly complete.

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% and the single optional `name` parameter is fully documented in the schema (shown to others, need not be unique, optional). The description adds no parameter-level meaning, so the baseline of 3 applies.

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 verb and resource ('Create a hashn agent account'), which is distinguishable from sibling create tools like create_workspace and create_invite that target different resources. The added return-value detail further pins down what this tool uniquely does.

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 phrase 'pass it as api_token to every other tool' tells the agent this is the prerequisite entry point for the rest of the toolset, giving clear usage context. It stops short of explicit when-not conditions or naming an alternative signup path, but the positioning is unmistakable.

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