set-trace-tag

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

Annotations indicate readOnlyHint=false (write operation) and openWorldHint=true, which the description does not contradict. The description states the basic action but does not disclose additional behavioral traits such as whether the tag overwrites an existing tag with the same key, what happens if the trace does not exist, or any authorization requirements. It adds minimal value 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?

The description is a single, concise sentence that front-loads the purpose. There is no wasted information, but it could be slightly expanded to include more context without losing efficiency.

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?

Given the simplicity of the tool (3 required parameters, no output schema, and annotations providing basic safety info), the description is adequate but not complete. It does not explain behavior when a tag with the same key already exists (overwrite vs. error), whether the operation is idempotent, or what happens if the trace does not exist. These are common concerns for a tagging 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?

The input schema describes traceId (no description), key ('Tag key'), and value ('Tag value'), giving 67% schema description coverage. The tool description does not add any additional parameter-level semantics, such as format constraints for the tag key/value or what traceId should look like. It relies on the schema, which has a minor gap for traceId.

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 'Add a custom key-value tag to a trace' uses a specific verb ('Add') and clearly identifies the resource ('trace'). It distinguishes this tool from sibling tools that operate on other entities like runs or experiments (e.g., set-run-tag, delete-trace-tag).

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?

No explicit guidance on when to use this tool versus alternatives. While the resource is clear from the name, the description does not mention that this tool is for traces specifically, nor does it reference when to use set-run-tag for runs or delete-trace-tag for deletion. The context is implied but not stated.

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