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

Annotations already cover read-only, idempotent, non-destructive, closed-world, so the description's added value is the error taxonomy and the return content detail (which settings are included beyond list-level basics). That is useful behavioral context beyond the annotations, though it stops short of describing response shape or any rate/permission nuances.

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?

Content is front-loaded: the returned-field inventory comes first, error conditions last. The opening line 'Get an agent' merely restates the title, and the error-code sentence duplicates the input schema, so a small amount of the text does not earn 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?

With no output schema, the description carries the return-value burden and does so by naming the notable settings returned, plus the two failure modes. It is nearly complete for a simple single-resource read; only the overall response envelope/format is unspecified.

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?

There is a single parameter with 100% schema description coverage, so the schema already documents agent_id and its error semantics. The description's 403/404 mapping largely repeats the schema text rather than adding new meaning, 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 states a specific verb+resource (retrieve one agent with its settings) and enumerates the distinguishing fields: Main Instructions, AI handoff, comment auto-hide, ai_stop_enabled/ai_stop_when. It explicitly contrasts with the list tool ('besides the basic details the list returns'), so an agent can distinguish it from list_agents without reading schemas.

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?

It clarifies the selection context by contrasting single-agent retrieval against the list, and gives concrete outcome conditions (404 for unknown/deleted/other-company agents, 403 for agents off the key's list). It does not explicitly address when to prefer get_agent_setup or get_agent_analytics, so the sibling exclusions are implicit rather than stated.

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