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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false), and the description adds genuinely useful context beyond them: it does not actually send mail or reach anyone, so no confirmation is needed, and it requires a Cotlet API key with app access. This clarifies the practical side effects of a write operation.

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?

Four short sentences, front-loaded with the core action and immediately followed by scope, side-effect clarification, and the auth prerequisite. Little waste, though the leading 'Zola:' prefix is redundant with the title.

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 two-parameter state-update tool with no output schema, it covers purpose, scope, side effects, and auth requirements. An agent has enough to call it correctly; only explicit alternative-tool routing is missing.

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%, with the enum for 'type' and guest_id both documented in the schema, so the baseline is 3. The description reinforces that it applies to one guest and to either mail type, but adds no format or sourcing detail beyond the schema.

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 specific verb+resource: tracking that a guest received a Save the Date or invitation, and scopes it to the 'Address Envelopes' mail tracking for one guest. This clearly separates it from siblings like zola_mark_thank_you_sent or zola_record_rsvp, though it never names those alternatives explicitly.

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?

Implies usage ('Track that a guest has received...') and adds a useful operational note that it runs without asking first, but gives no explicit when-to-use/when-not or routing guidance against sibling tools such as zola_record_rsvp or zola_mark_thank_you_sent.

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