get_marketplace_item

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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial context beyond that: it clarifies no installation or template creation occurs, requires an API key, and warns that listings are third-party claims not verified by MisarMail. These behavioral and trust details are valuable and not redundant 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 compact and well-structured: a clear opening sentence, followed by usage context, then safety and prerequisite warnings. Every sentence earns its place with no filler or repetition.

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 read tool with good annotations and schema, the description fully covers the workflow (after list, before adoption), prerequisites (API key), return contents (preview, author, installation instructions), and a crucial trust caveat. No output schema is needed since the description specifies what is returned.

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% for item_id ('Marketplace item ID'), so the schema already documents the parameter fully. The description adds no additional semantic detail about the parameter, so baseline 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 uses a specific verb+resource: 'Get one marketplace listing in full, with its preview, author, and installation instructions.' It clearly distinguishes from siblings like list_marketplace_items by specifying it retrieves a single item with full detail, and it positions itself as the read step before adopting.

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?

Explicit when-to-use: 'Use it after list_marketplace_items to inspect a template before adopting it.' It also states what it is not for: 'this is the read step, and it does NOT install anything into the account or create a template.' This is strong guidance with alternatives and exclusions.

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