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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful behavioral context by specifying the output as JSON text and listing the manifest sections included, plus the workflow purpose. It does not contradict the annotations; it complements them.

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 two tight sentences with no redundancy. The first sentence states the core action and output contents; the second gives operational guidance. Every clause earns its place.

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 simple, single-parameter read-only tool with 100% schema coverage and no output schema, the description provides sufficient information: what is returned, how to obtain the slug, and why to use the tool. It also fits into the surrounding tool workflow, making it complete for an agent to invoke correctly.

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 for the single 'slug' parameter is 100%, including the explicit note that it is not a full URL and must come from nexez_search or nexez_directory. The description echoes this and adds usage intent, but does not materially deepen parameter semantics beyond the schema.

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 identifies the action ('Fetch'), the resource ('one listing's structured agent manifest'), and the output format ('as JSON text'). It also enumerates the manifest contents (seller profile, offers, configuration requirements, published actions), distinguishing it from the search, directory, and validation sibling tools.

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 explicitly states the slug source ('returned by search or directory') and the recommended workflow position ('inspect exact offer identifiers and requirements before validation'). This gives the agent clear guidance on when to call this tool relative to its siblings.

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