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

Annotations already mark read-only/idempotent, and the description adds valuable behavior beyond them: unknown ids and other-customer ids both return found:false with no distinguishing signal, by design, and the tier restriction is stated. This is exactly the kind of extra behavioral context an agent needs.

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?

Three sentences, front-loaded with the main behavior, no wasted words. Every clause earns its place: id source, not-found behavior, design rationale, and access tier.

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-only tool with full schema coverage and an output schema, the description is complete. It covers the success case, failure semantics, privacy boundary, and access tier, so an agent can call it without surprises.

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 is 100% and the schema already describes agent_id as coming from save_agent/list_agents. The description adds 'caller's own' and 'standing' qualifiers, which clarify ownership and lifetime in a way the schema alone does not.

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?

Description uses specific verb 'fetch full detail' with clear resource: one of the caller's own standing agents by id. It also names the source functions (save_agent/list_agents) and implicitly contrasts with get_agent_run.

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 clear context: use this when you already have an agent_id from save_agent/list_agents and need full detail. It does not explicitly list when to prefer a sibling tool, but the ownership and id-source constraints make the intended usage unambiguous.

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