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

Annotations mark this as a non-readonly, non-destructive, non-idempotent write; the description adds the key nuance that it produces a *draft* rather than a sent invitation, and it discloses the return payload (preview link, get link, filled vs. missing fields). It stops short of stating auth needs, whether drafts expire, or what happens on ambiguous input.

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 sentences, no filler, with the core action front-loaded and the optional parameter and return shape trailing. Every clause carries information.

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 creation tool with no output schema, the description covers input expectations and the shape of the response, which is what an agent needs to call and interpret it. Missing are failure modes (e.g., unusable request text) and how 'what is still missing' should be handled downstream.

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%, so baseline is 3, but the description earns a bump by enumerating what the 'request' string should contain (who it is for, age, date, time, place, theme, colors) — actionable content guidance the schema's 'Everything the user said about the party' does not supply. design_id is only restated, not enriched.

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 ('Create an invitation draft') and scopes it to plain-language party descriptions. The word 'draft' implicitly separates it from change_invitation and get_invitation, but neither sibling is named, so the differentiation is inferred rather than explicit.

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 a clear usage condition for the optional path: pass design_id 'if the user picked one,' and points at find_designs as the source of that id. It does not say when to reach for change_invitation instead of creating a new draft, so the mutation-vs-edit decision is left to inference.

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