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

Goes well beyond the annotations by disclosing the API-key env var (SIGNUPBOUNCER_API_KEY), a 1.5-second call limit, and the fail-open behavior ('any failure lets the signup through'). These are exactly the operational traits an agent needs and cannot derive from readOnlyHint/idempotentHint.

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 what it returns before the usage cue and the behavioral caveats. Every clause carries information an agent needs; nothing is redundant.

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 an output schema present, the description needn't detail return values, and the annotations already cover the safety profile. Adding the env var, timeout, and fail-open semantics makes it complete for a code-generation 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?

Schema coverage is 100%, so the enum values are already documented. The description adds meaning beyond the schema by annotating one value semantically ('supabase (a hook, no code)'), which slightly exceeds the baseline 3 for a fully-covered single parameter.

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?

Names a specific verb and resource: 'Returns the steps and the copy-paste code that checks new signups', with an explicit enumeration of supported stacks. This cleanly distinguishes it from siblings like check_email and lookup_burner_domain, which perform lookups rather than produce integration code.

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?

'Use it when the user is building or changing a signup, register or auth flow' gives a clear triggering condition. It lacks an explicit when-not or a named alternative among the siblings, but the condition is concrete enough to route most calls correctly.

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