list_discovered_agents

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

Beyond the annotations (readOnlyHint, idempotentHint), it discloses authentication needs, a 200-item limit, ordering by most recently seen, the response wrapper format, and the untrusted_fields security caveat. This provides substantial behavioral context not present in the structured 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?

Every sentence contributes necessary information: prerequisite, core definition, usage trigger, limits, output wrapper, and security warning. The description is dense but free of filler and front-loads the most important operational facts.

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 no output schema, the description fully explains the response shape, fields, result count, ordering, and the untrusted-fields warning. Combined with sibling context, it gives an agent everything needed to call the tool correctly and interpret its result.

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 tool has zero parameters and schema coverage is 100%, so the baseline is 4. The description adds no parameter-specific detail because none is needed; it instead clarifies output and usage context, which is appropriate.

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 uses a specific verb and resource, defining discovered agents as 'trace sources that sent spans but match no registered agent.' It lists the returned fields and clearly distinguishes this tool from the sibling list_agents by focusing on unregistered sources.

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 an explicit trigger: 'Call this when traces arrive but an agent shows none of them.' It also names the follow-up tool, adopt_discovered_agent, and states the required API key scope, so an agent knows exactly when and how to proceed.

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