check_api_key

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

With no annotations, the description carries the full behavioral burden. It discloses the underlying mechanism: it asks the PartnerAuthentication service whether the key is registered and active, and contrasts that with the misleadingly permissive heartbeat endpoints. This adds real behavioral context beyond the tool name.

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 with no filler. The main purpose is front-loaded in the first sentence, and the second sentence earns its place by explaining why this endpoint is necessary despite heartbeat endpoints accepting any key.

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 zero-parameter validation tool with an output schema, the description is complete. It tells the agent exactly what the tool checks, why that check is necessary, and which service it contacts. No additional detail is needed for correct invocation.

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 has zero parameters, so the baseline is 4. The description adds useful context about the 'configured' key even though no input is required, which is sufficient for an agent to understand how invocation works.

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 opens with a specific verb-resource pair: 'Validate the configured LIS API key.' It also distinguishes this tool from the sibling data-retrieval tools by framing it as the only real authentication check, so an agent can immediately tell what it is for.

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 explains why this tool matters ('heartbeat endpoints accept any key, so this is the only real check'), giving strong contextual guidance for when to call it. It does not explicitly name sibling alternatives or exclusions, but none of the siblings perform API-key validation, so the context is sufficient.

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