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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered; the description adds value by enumerating the concrete data returned (plan, sites used, site limit, dashboard URL), which matters because no output schema exists. It does not discuss auth failure modes or error behavior, keeping it short of a 5.

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?

A single front-loaded sentence with a colon-delimited field list; every clause earns its place and nothing is padded.

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 input parameters and no output schema, the description must carry return-value information, and it does so by listing the main fields. It stops short of describing response shape or edge cases (e.g. invalid key), but is adequate for a simple read tool.

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 tool takes zero parameters, so there is no parameter semantics to explain; the baseline of 4 applies. The description correctly implies no input is needed by framing the lookup as keyed off the API key itself.

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 specific resource and scope: the account tied to the current API key, and enumerates the returned fields (id, name, plan, site usage, site limit, dashboard URL). It is clearly distinct from siblings like get_stats or list_sites, though it never explicitly names those alternatives.

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 'the Hooky account this API key belongs to' implies usage context (identity/plan lookup for the authenticated key), but there is no explicit when-to-use or when-not-to-use guidance relative to siblings. An agent can infer it is the entry point for account metadata, but must reason about the boundary itself.

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