Validate API key

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety and network profile is covered. The description adds useful context (auth-diagnosis use case) but says nothing about rate limits, what happens on an invalid key, or cache lifetime beyond what the schema notes for refresh.

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 return value, then the usage triggers. Every clause carries information and none 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 no output schema, the description helpfully enumerates the returned profile fields, and annotations carry the safety profile. The only gap is failure behavior — it does not say whether an invalid key raises an error or returns a negative result, which matters for a validation 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 description coverage is 100% and the single 'refresh' parameter is fully documented in the schema ('Bypass the cache and re-query Nexus'). The description adds no additional parameter meaning, so the baseline 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 (validate) and resource (Nexus API key), and goes further by naming the returned payload (name, user id, premium/supporter status). This distinguishes it clearly from read-oriented siblings like nexus_get_mod or nexus_list_mods.

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?

Gives two explicit triggers: 'call this first when authentication looks broken' and 'to learn the current user before nexus_list_author_mods'. It names a concrete sibling and the dependency condition that selects this tool, leaving little to inference.

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