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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true), the description discloses that no notification is sent to the guest, that the mutation is reversible by resubmitting the old address, and that a Cotlet API key with app access is required. These are exactly the behavioral facts an agent needs before mutating data.

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?

Purpose is front-loaded, followed by behavior and then the auth prerequisite; every sentence carries information. The 'Zola:' prefix duplicates the title and is minor waste, keeping it just under a 5.

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 mutation with no output schema, the description covers purpose, side-effect scope, reversibility, and auth requirements. It could note what the response looks like on success, but the safety-relevant content is complete.

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 two parameters are fully documented in the schema (address field breakdown, guest_id sourced from list_guests). The description adds no syntax or format detail beyond that, so the baseline 3 is appropriate.

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 names a specific verb (set/replace) and resource (one guest's mailing address used for Save the Dates and invitation envelopes), and anchors it to the 'Address Envelopes' page. It is clearly distinguishable from siblings like zola_add_guest or zola_list_guests, which do not touch envelope addressing.

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?

It gives actionable context: nothing is sent to the guest, so it can run without confirmation, and re-calling with the old address reverses it. This tells the agent when it is safe to use, though it does not explicitly name a competing alternative tool.

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