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

Annotations already disclose readOnlyHint=false, destructiveHint=false, so the safety profile is largely covered. The description adds that the update happens 'in-place' and that auth can be rotated, which is helpful context. It does not explain partial-update behavior (whether omitted fields are preserved or cleared) for these nested, complex parameters.

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 tight sentences, purpose first, parameter-combination guidance second, with no wasted words. Appropriately sized for a four-parameter update tool.

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 no explanation, and the schema fully documents the nested params. The description covers purpose and parameter combinations, but omits sibling disambiguation and partial-update semantics, leaving minor gaps for a complex nested-object mutation.

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?

With 100% schema description coverage the baseline is 3, but the description goes beyond the schema by explaining how parameters combine: spec alone updates the definition, auth alone rotates credentials, or both together. That combination logic is not derivable from the per-parameter schema descriptions.

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 states a specific verb and resource ('Update an existing spec and/or its auth configuration in-place'), which is far more than a restatement of the title. It does not, however, differentiate itself from closely related siblings such as manage_credentials or save_spec, 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?

It gives clear operating guidance for the three call modes ('spec alone to update the definition, auth alone to rotate credentials, or both'), which is useful. But it says nothing about when to prefer this tool over alternatives like manage_credentials (for credentials) or save_spec, leaving the sibling-selection decision to inference.

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