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

With no annotations, the description carries the full behavioral burden; it does disclose that this is a read and that the result contains no secrets, which is genuinely useful safety context. It omits error behavior for a missing identity, what happens when multiple identities exist, and what fields beyond the inbox address are returned.

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?

Two short sentences, front-loaded with the action and followed by the most decision-relevant property (no secrets). Nothing is redundant.

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 single-optional-parameter read with no output schema and no annotations, the description is nearly complete: it names the payload highlight (inbox address) and its confidentiality. Only the returned field set and error semantics are missing, which are minor at this complexity.

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 single identity_id parameter is fully documented in the schema, including the omission rule for single-identity accounts. The description adds nothing about the parameter, so the schema does all the work and 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?

"Read one identity" gives a specific verb plus resource, and "including its inbox address" adds scope detail. It does not explicitly differentiate itself from siblings like get_email_code or list_events, so an agent must infer the boundary from the noun alone.

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?

There is no explicit when-to-use statement, no mention of alternatives, and no prerequisites. Usage is only implied by the resource name and the mention of the inbox address, which suggests the tool is for resolving an identity to its address.

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