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

With no annotations provided, the description carries the burden of behavioral disclosure. It does convey that this is a read-only directory listing and that the market structure graph is included as the first entry, which is useful context. However, it doesn't disclose details like whether the list is paginated, sorted, or if it includes inactive agents, which would be valuable for a directory tool.

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 compact and front-loaded with the core purpose ('agent directory'), then adds the key details about what entries include. The final sentence about the market structure graph is a useful behavioral note. It earns its place without excessive length.

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?

For a zero-parameter listing tool with an output schema present, the description is reasonably complete. It tells the agent what the directory contains and highlights the market structure graph entry. It could be more complete by noting whether the list is exhaustive or filtered, but the output schema likely covers return structure.

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, so the schema provides no parameter semantics to work with. The description compensates by explaining what the returned directory contains (agents, A2A cards, MCP endpoints, assets/sectors, market structure graph), giving the agent a clear expectation of the output without needing parameter details.

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 clearly identifies the tool as a directory listing of registered research/data agents, including their A2A card/MCP endpoints and covered assets/sectors. It distinguishes itself from siblings like find_agents and hire_agent by focusing on the directory/market structure aspect, though it doesn't explicitly name those alternatives.

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?

The description implies this is the tool to use for browsing the agent directory and market structure, and notes the market structure graph is the first entry. However, it doesn't explicitly state when to use this over find_agents or other sibling tools, leaving the selection criteria to inference.

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