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

Adds substantial context beyond the annotations: signed link with 1-hour validity for non-public activities, organizer-login requirement, the prerequisite that the activity be published and not cancelled, and the key caveat that it only generates files and never sends to recipients. The non-readOnly/non-idempotent annotations are consistent with this creation behavior.

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?

Dense but organized with bracketed sections (auth, chain, pitfalls) and the core action front-loaded. Every sentence carries information; length is justified by the tool's complexity, though it is information-heavy for a single block.

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?

Covers authentication, prerequisites, format semantics, delivery-chain expectations and pitfalls for a 6-parameter mutation-style tool with no output schema. Nothing an agent needs to invoke it correctly 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 description coverage is 100%, so the schema already documents each parameter, giving a baseline of 3. The description goes further by explaining format-to-style mappings (docx=official, pdf=official/business, png=all styles) and the scope=list/pick relationship, adding meaning 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 precise verb+resource (render the invitation letter into a file and return a download link) and scopes it against siblings: get_activity_letter reads, update_activity_letter edits, this tool produces output. An agent can distinguish it from the many letter-related siblings without opening schemas.

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?

Explicitly gives the order-of-operations chain (get_activity_letter to inspect style/format → this tool → deliver png as image, PDF/Word link in reply), states login/organizer requirement, and names the format-to-style constraints. No ambiguity about when to use it.

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