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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description correctly inherits the safety profile without over-explaining. It adds useful behavioral detail by framing the output as an 'editable surface' designed to be fed back into update_agent, which shapes expectations about the return value.

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 entire purpose is conveyed in a single, front-loaded sentence with zero filler. Every phrase earns its place: 'one agent' limits scope, 'editable surface' describes the returning shape, and the update_agent reference documents the round-trip contract.

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 fetch tool with readOnly and destructiveHints provided, this description is close to complete. The only unmentioned details are error/not-found behavior and exact return schema, but the 'round-trippable with update_agent' phrasing signals the return format sufficiently.

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 only parameter agent_id is well-documented with its source providers. The description adds nothing specific about the parameter itself, so the baseline of 3 applies because the schema carries the full semantic weight.

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 uses a specific verb and resource: 'Fetch one agent's editable surface'. The phrase 'one agent' clearly distinguishes it from list_agents while 'editable surface' and the reference to update_agent define it as the read-for-editing counterpart to get_catalog, get_wiring, and probe_agent.

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 communicates when to use this tool by noting that its result is 'round-trippable with update_agent', effectively making it the fetch step before an edit. This is clear context, though it does not explicitly name alternatives or list when-not-to-use conditions.

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