Retrieve agent

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior: passing the `gumball` or `analytics` alias resolves to the caller's own copy and 'creates it on first use' — a side effect not captured by any annotation — plus how the alias is echoed back in responses. It stops short of describing error behavior or permissions.

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?

Front-loaded with the core action, followed by the alias note, with no wasted preamble. The trailing 'Read operation.' partially duplicates the readOnlyHint annotation and could be dropped, but the text is otherwise tight and well ordered.

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 two-parameter read tool with 100% schema coverage and full annotations, the description covers the essentials and adds the alias-resolution behavior the agent could not otherwise know. With no output schema it also hints at the return shape ('responses report the alias back as the agent's id'), though it omits error and not-found behavior.

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%, so the baseline is 3, and the schema already documents both `account` and the alias-accepting `agent_id`. The description goes beyond the schema by explaining what the alias actually resolves to and the create-on-first-use semantics, adding real meaning to the `agent_id` parameter.

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 and resource with scope: 'Retrieve a single agent by ID,' which implicitly separates it from list_agents and the create/update siblings. However, it never names an alternative tool, so differentiation is by inference rather than explicit contrast, keeping it just below a 5.

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?

Usage is implied by the singular 'by ID' framing, but there is no explicit when-to-use guidance, no statement of when to prefer this over list_agents or retrieve_agent_version, and no exclusions or prerequisites. The alias discussion is contextual but not routing guidance.

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