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

With no annotations provided, the description carries the full behavioral burden. It discloses that functions are Bitcoin Schema posts, which is a domain fact, but it does not disclose pagination, default scope, ordering, or any side effects. The verb 'List' implies a read-only operation but that is not made explicit.

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 concise and the core action is front-loaded in the first sentence. The second sentence provides useful conceptual context but is somewhat cryptic ('the marketplace IS the social graph'), so it is slightly less crisp than a flatly clear alternative.

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 tool with a single optional parameter and no output schema, the description is adequate for basic identification. However, it does not explain how results are shaped, whether the 'app' filter maps to any special marketplaces, or when to prefer this over sibling tools, leaving some gaps for an agent.

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% because the only parameter 'app' already has a clear description ('Filter by app (default: all)'). The tool description adds no parameter-specific meaning beyond the schema, so the baseline of 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 states a clear verb ('List') and resource ('registered functions (marketplace services)'), and adds context that these are Bitcoin Schema posts. The 'marketplace services' parenthetical helps distinguish the resource from generic post/feed tools, though it does not explicitly name a sibling alternative.

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?

No guidance is given about when to use this tool versus alternatives like peck_feed or peck_search. The description implies the tool lists marketplace services, but it never states exclusions, prerequisites, or criteria that would route an agent to this tool over its many siblings.

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