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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds that the response includes provider and limits, which is genuinely useful given there is no output schema, but it says nothing about auth requirements, error behavior for an unknown slug, or rate limits.

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 compact sentences with the action and scope front-loaded; nothing is padded or repeated. Every clause carries information.

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 one-parameter read tool with annotations covering safety and full schema coverage, this is nearly complete, and the mention of provider + limits partially compensates for the missing output schema. It only lacks guidance on retrieval-vs-list selection and failure cases.

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 sole parameter is documented in the schema as 'The virtual key slug.' The description's phrase 'by slug' restates that without adding format, source, or validation detail. Baseline 3 applies when the schema does the heavy lifting.

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 (Get) and resource (a single virtual key) and adds the retrieval key (by slug) plus what the payload contains (provider + limits). The word 'single' implicitly separates it from portkey_list_virtual_keys, but the sibling is never named explicitly, so it stops short of a 5.

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?

There is no when-to-use statement, no guidance on choosing this over portkey_list_virtual_keys, and no prerequisites or notes for a slug that does not exist. The only usage signal is the embedded endpoint 'GET /virtual-keys/{slug}', which is documentation rather than routing guidance.

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