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

Annotations only say this is a non-read-only, non-destructive, non-idempotent, open-world mutation. The description adds the crucial side effect (on a live AUTOPILOT event the corrected address is mailed its invite), the reason for it, and the differing permission requirements (write vs write+send). No contradiction with destructiveHint=false, since the send is a notification rather than data loss.

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, and each clause (draft vs live, mail side effect, share-link exclusion, permissions) carries distinct information. The heavy em-dash and parenthetical nesting makes it denser than ideal, but there is little true waste.

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; what remains — applicability, side effects, permissions, and the no-guest-list edge case — is fully covered for a 4-parameter mutation 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?

Schema coverage is already 100%, so the baseline is 3, but the description reinforces that the name change is draft-only ('a name can be changed there too' on a draft) and that the guest argument targets one specific guest. It adds modest but real meaning over the schema rather than repeating it verbatim.

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 and resource ('Corrects one guest's email address') and immediately scopes it to drafts or live events, which cleanly separates it from add_guests, remove_guests, and update_event. It even equates itself to the console action ('the console's own "Change address"'), removing ambiguity about intent.

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?

Gives explicit when-to-use (draft_ id or live event) and when-not ('A live classic (share-link) poll has no guest list, so there is nothing to correct there'), plus the differing permission preconditions per context. The agent can decide applicability without consulting siblings or schemas.

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