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

The description goes well beyond the readOnlyHint/idempotentHint annotations by disclosing that an error is returned if the slug is unknown or the agent is not listed, and by adding a meaningful caveat that payment metadata is self-configured and published for interoperability rather than as an endorsement. It also explicitly confirms the read-only nature, aligning with 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 well-structured: a front-loaded main clause, a usage pointer, a caveat, an error-behavior note, and an example. The first sentence is somewhat long because it enumerates many manifest fields, but this is justified given there is no output schema and those details help an agent anticipate the return content.

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 read-only lookup with two well-documented parameters and no output schema, the description is complete: it names the return contents, identifies how to discover valid slugs, notes failure behavior, clarifies a potential trust concern, and confirms non-destructiveness. No critical context an agent would need to call this tool successfully is missing.

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 schema already fully documents both 'slug' and 'response_format'. The description reinforces the slug semantics and provides an example, but it does not add meaning beyond the schema, such as clarifying response_format behavior or edge cases. A baseline of 3 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 opens with a specific verb and resource: 'Get the full Sato Agent Passport manifest (sato.agent.manifest/v1) for one REGISTERED agent by slug.' It clearly differentiates this from sibling get_* tools by naming the unique resource type and outcome, and the title 'Look up one registered agent' reinforces this.

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 gives clear context for when to use this tool — when you need the full passport manifest for one registered agent — and explicitly names onchain_agent_search_agents as the way to find slugs, which is a useful pointer to an alternative tool. It stops short of explicitly stating when not to use this tool or contrasting it with other get_* siblings, but the guidance is sufficient for an agent to route correctly.

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