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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds genuinely non-obvious behavior: sender-name edits apply to subsequent sends only, and the address/access are untouched — useful effect-scoping beyond the annotations.

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 tight sentences, zero filler, with the scoping constraint front-loaded and the side-effect caveat following. Every clause earns its place.

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?

With an output schema present, return values need not be explained, and annotations cover safety. The description supplies scope and side-effect timing; the only real omission is any guidance on prerequisites or alternatives, which is minor for a simple idempotent rename.

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 67%, with 'name' and 'sender_name' richly documented (null/blank semantics, byte limits) in the schema itself. The description's note that sender-name changes affect subsequent sends rather than historical mail adds meaning for sender_name beyond the schema, though inbox_id gets no descriptive treatment (acceptable for a plain UUID).

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 precise verb+resource ('Edit shared inbox names') and immediately bounds the scope with 'without changing the address or access', which separates it from address/access-affecting operations. Among siblings (create_inbox, delete_inbox, get_inbox, list_inboxes) it is unambiguously the only name-editing tool.

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 only implied: the agent can infer this is the tool for renaming an inbox, but there is no explicit when-to-use/when-not-to-use guidance and no named alternative. The 'without changing the address or access' clause hints at exclusions but never states what to use instead.

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