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

Annotations already indicate destructive and non-read-only behavior; the description adds useful nuance by specifying that only expectedOutput is replaced and that file pairing is immutable. This is compatible with idempotentHint and adds behavioral context beyond the annotations.

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 efficient sentences: the first states the main action, the second states a critical constraint. No filler, no repetition of schema content.

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 a detailed input schema, annotations, and an output schema available, the description covers the tool's mutation scope and its essential limitation. It could mention side effects more explicitly, but the surrounding structured signals fill most remaining gaps.

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?

Input schema descriptions cover 100% of the 5 parameters, including detailed semantics for expectedOutput, environment, and workspaceId. The description contributes general scope but does not add per-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?

Description uses a specific verb ('Replace'), names the resource ('evaluation item') and the exact field ('expected output'), which clearly differentiates it from sibling tools like add_evaluation_items and delete_evaluation_item. The 'evaluations group' parenthetical and the note about file pairing further narrow the scope.

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?

Explicitly states what the tool can do (replace expected output) and what it cannot do (change file pairing), and points to delete-and-re-add as the alternative workflow. This gives the agent clear when-to-use and when-not-to-use guidance.

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