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

Annotations already carry the read-only, idempotent, non-destructive profile, but the description adds several non-obvious behaviors: unknown ids and other-customer ids both return found:false rather than an error, and there is deliberately no distinguishing signal between the two cases. It also discloses a tier/entitlement constraint (sp500+, sample rejected), which is authorization context no annotation provides.

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 core action and followed by the exception semantics and entitlement note. Dense and mostly waste-free, though the parenthetical '(sample rejected)' is slightly cryptic without additional context.

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?

An output schema exists, so return structure needn't be restated, and the description covers the one genuinely surprising return behavior (found:false as a non-error for two indistinguishable cases) plus the entitlement gate. Nothing an agent needs to call it correctly is missing.

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% and the schema already states that agent_id comes from save_agent or list_agents. The description reinforces that the id must belong to the caller but adds no format, boundary, or validation meaning beyond the schema. 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?

States a specific verb (fetch), resource (one of the caller's own standing agents), and identifier source, with 'full detail' distinguishing it from the list_agents summary view. An agent can tell this apart from list_agents, get_agent_run, and get_agent_memory without opening any schema.

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 tells the agent where the id comes from (save_agent/list_agents) and scopes the lookup to the caller's own agents, which implicitly excludes other-customer ids. It does not explicitly contrast with list_agents as a bulk alternative or state when not to use this tool, so it falls short of the top score.

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