Get AgentDNS Entity Card

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

Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false. The description adds substantial behavioral context: fallback to .well-known/agent.json, details of what the card contains (identity, endpoints, pricing, schemas), and error codes (404, 5xx). No contradiction with 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 well-structured with sections for Args and Errors. It is somewhat lengthy but every sentence adds value (e.g., fallback, card contents, usage for zyndai_call_agent). It could be slightly more concise, but overall it is organized and informative.

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?

Although there is no output schema, the description explains what the card contains (identity, endpoints, pricing, schemas) and how to use the schemas. It covers the main use case and error scenarios. It could mention that the output is a JSON object, but overall it is complete for a tool retrieving a signed entity card.

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 coverage is 100%, with the schema providing a clear description of entity_id ('AgentDNS entity ID — looks like 'zns:a90cb541…' or 'zns:svc:…''). The tool description adds only minor context ('Get one from search/resolve results'), so the description adds little beyond the schema.

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 states it fetches the full signed entity card for an agent or service. It specifies the resource (entity card), the verb (fetch), and distinguishes from siblings like zyndai_call_agent, which uses the card to call the agent. The mention of the GET endpoint further clarifies the action.

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 explains when to use the tool: to retrieve the entity card, especially to obtain input_schema and output_schema for constructing messages for zyndai_call_agent. It also describes fallback behavior. However, it does not explicitly state when not to use this tool compared to alternatives like zyndai_list_agents or zyndai_search_agents, though the context implies it's for a specific entity.

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