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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds useful context by scoping the result to the bearer credential on the current connection, which helps the agent understand that the identity is connection-specific rather than global.

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 description is a single, tightly written sentence that leads with the verb and resource, with no filler, redundancy, or unnecessary elaboration. It earns conciseness without sacrificing meaning.

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 zero-parameter, read-only identity lookup, the description plus annotations provide enough context for correct selection and invocation. It does not specify the exact return shape, but 'identity' adequately indicates the expected result for this simple tool.

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?

The tool has zero parameters, so the schema is empty and there is no parameter semantics burden on the description. The description appropriately explains what the tool returns in terms of the credential context, which is sufficient.

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 ('Read'), a specific resource ('identity'), and the scope ('associated with the bearer credential on this connection'). This clearly differentiates it from sibling tools like register_agent or get_agent_guide, making the tool's purpose unambiguous.

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 clearly implies when to use this tool: when an agent needs the identity tied to the current connection's credentials. It does not explicitly name alternatives or state when not to use it, but among the sibling tools there is no direct competing identity-checking tool, so the usage context is clear.

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