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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without the description. The description contributes no additional behavioral context - no scope of the registry, ordering, pagination, or result size - beyond noting that capabilities accompany each agent.

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?

One short sentence, front-loaded with the verb and resource, with no filler. It is efficient, though 'Discover' is a slightly vaguer verb choice than 'List'.

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 is the only place to convey what comes back, and 'and their capabilities' only partially does so - it omits the agent identifier, count, and whether filtering is reflected in results. Adequate but thin for a discovery tool with a filtering parameter.

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 the single capability parameter is already documented as a filter. The description adds nothing about how the filter behaves (exact match vs substring, multiple capabilities), and its 'all registered agents' phrasing mildly understates that filtering is possible. 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?

The description gives a clear verb+resource ('Discover all registered agents') and adds that capabilities are included. It does not distinguish itself from overlapping siblings such as find_agents_by_capability or get_agent, and the word 'all' sits awkwardly next to an optional capability filter.

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?

There is no when-to-use guidance, no prerequisites, and no mention of the near-duplicate sibling find_agents_by_capability, which is exactly the alternative an agent would need to weigh against this tool. The agent is left to infer selection from the name alone.

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