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

Annotations already declare readOnlyHint=false, idempotentHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description goes further by translating idempotentHint into concrete behavior ('repeated requests with the same idempotency key return the existing draft') and by disclosing return values (preview URL, private management token) and content prohibitions. It stops short of permission/auth requirements and whether drafts can later be deleted or published.

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?

Five sentences, front-loaded with purpose then return values, then constraints. Each sentence carries distinct information (outcome, outputs, acceptance rules, prohibitions, idempotency) with no obvious filler, though the acceptance-criteria list is dense enough to be hard to scan.

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 no output schema, the description usefully documents the return shape, and it covers content rules and idempotency. But for a ten-parameter, one-nested-object tool, the absence of any explanation for the people/metadata parameters (sender, recipient, occasion, theme, message) is a real completeness gap an agent would notice when filling the required fields.

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?

Top-level schema description coverage is 0%, so the description must carry parameter meaning. It does well for the game payload and idempotencyKey, but eight of ten parameters (recipient, sender, title, concept, message, occasion, theme, recipientEmail) receive no explanation at all in either field. Critically, it never clarifies whether recipientEmail triggers an actual send or is merely stored, despite the tool being a 'draft'.

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 states a specific verb and resource ('Saves a supplied self-contained HTML game') and the resulting artifact ('as a free private draft'), plus what is returned. It is clear, but it never differentiates itself from the adjacent write tools in the sibling list (make_game, revise_custom_game), leaving the agent to guess which save/create path applies.

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?

Usage is implied through the acceptance criteria ('accepted games have inline code...') and the idempotency contract, so an agent can infer what input is valid. However, there is no explicit when-to-use guidance and no routing versus make_game, revise_custom_game, or export_gift, which is the main decision an agent faces here.

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