Which Marketplaces Are Loaded

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

Beyond the annotations indicating a read-only, idempotent operation, the description reveals the defensive import behavior and the semantic meaning of the 'skipped' field: a missing dependency removes a marketplace rather than crashing the server, and skipped entries were never queried. This context is not derivable from the annotations and is critical for interpreting results correctly.

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 front-loaded with the core purpose, then uses two clearly labeled sections ('Why this exists' and 'Return Format') that each add necessary context. Every sentence serves a purpose, and the markdown structure makes it easy for an agent to scan for the key trigger and return semantics.

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, read-only diagnostic tool with a rich output schema and safety annotations, the description covers everything an agent needs: what it lists, why missing marketplaces appear, when to invoke it, and what the skipped mapping means. No important operational detail is omitted.

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 accepts zero parameters, so there is no parameter semantic burden on the description. With an empty input schema and 100% schema coverage, a baseline of 4 is appropriate; the description cannot and need not add parameter-level meaning.

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: 'List which connectors this unified server actually mounted.' This clearly distinguishes the tool from the sibling marketplace search/card tools, which query individual marketplaces, by focusing on what is loaded on the server. The title 'Which Marketplaces Are Loaded' reinforces the same purpose.

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 an explicit trigger: 'Call this before concluding a marketplace has no results — if it is in ``skipped``, it was never queried at all.' It explains the failure mode where absent tools look identical to empty results, which tells the agent exactly when this diagnostic is needed. This is a clear, directive usage guideline.

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