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

Annotations already declare readOnlyHint=true, but the description adds behavioral context by explaining the tool is scoped to the active Space and that space_id can override this for one call. This clarifies the dependency on session state, which is valuable beyond the read-only hint.

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 concise sentences, front-loaded with the primary action and followed by necessary scoping context. No wasted words, every sentence contributes value.

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 get tool with readOnlyHint and no output schema, the description covers the core purpose, scoping, and override mechanism. It doesn't mention return format or error cases, but these are reasonably inferred for a fetch-by-id operation, and the description is sufficient for an agent to select and invoke the tool.

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 schema covers space_id in detail, but conversion_action_id has no description. The description adds clarity by indicating the tool fetches by id, and mentions space_id override, but does not fully compensate for the missing conversion_action_id format or constraints. Schema coverage is 50%, so the description provides only marginal added 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 clearly states the action: 'Fetch one conversion action by id.' This is a specific verb (fetch) with a specific resource (conversion action) and scope (by id), differentiating it from list_conversion_actions and other get_* tools. The resource and operation are unambiguous.

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 provides context on space scoping and points to set_active_space for switching, with an option to override per call. It implies this tool is for fetching a single known ID rather than listing all, though it doesn't explicitly mention list_conversion_actions as an alternative for browsing.

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