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

The description adds substantial context beyond annotations: free hosting, one URL per agent name, browse-only capabilities, no payment handler, idempotent name-to-URL mapping, and search privacy. However, with readOnlyHint=false, it could more explicitly state whether calling the tool registers or creates a profile entry rather than merely retrieving one.

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 information-dense and every sentence contributes context, but it is somewhat conversational and leads with background rather than the action. It could be tightened and front-loaded while preserving the useful constraints.

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 one-parameter tool with no output schema, the description gives enough context to understand the result (a hosted profile URL) and its limitations. The main remaining gap is not clarifying the write/registration side effect implied by readOnlyHint=false.

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%, so the parameter is already documented. The description still adds useful semantics by explaining the stable 'same name = same URL' mapping and providing a concrete agent_name example.

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 that the tool obtains a UCP agent profile URL hosted by Faceabot, with a specific verb and resource. It does not explicitly differentiate from sibling tools, but those siblings serve unrelated shopping/store lookup purposes, so the core purpose is still clear.

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 explains the triggering context: UCP stores ask for a meta['ucp-agent'].profile URL, and Faceabot can host one when the agent has no website. It also gives a key limitation ('browse-only ... cannot pay') but does not explicitly frame alternatives or when-not-to-use in a structured way.

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