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

Annotations declare a non-read-only, non-destructive, open-world operation, and the description adds genuinely useful behavior beyond them: the input must come from the user unmodified, and the response yields an API key the platform should persist in its connector configuration. It omits failure/validation behavior, so not 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?

Three tight sentences with the action and its input source front-loaded, followed by the handling rule and the output consequence. No filler and nothing buried.

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?

An output schema exists, so return values need not be explained, yet the description still flags the important side effect (an API key to save), and it warns against fabricating the key. It is complete enough to call correctly, though it says nothing about the optional 'client' parameter's role or error handling.

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%, so both 'key' and 'client' are already documented in the schema; baseline 3 applies. The description adds only the nuance that the key is 'short' and user-supplied, which is marginal beyond the schema text.

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 and resource: 'Complete the CortexPlus connection' using a short authentication key received by email. It clearly distinguishes itself from the signup sibling by framing this as the post-signup completion step rather than account creation.

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 an explicit precondition and sequence: ask the user to paste the key, then call this tool, and 'never guess or invent the key.' It does not name an alternative tool or state when this should NOT be used (e.g., re-connection cases), so it stops short of a 5.

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