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

Goes well beyond the annotations: discloses zero credit cost, that the response is the whole board plus the new card, and the full auth path (OAuth via host prompt or an acd_live_ Bearer key). One meaningful gap remains for a mutation tool: idempotentHint=false is not surfaced, so nothing warns that a retry will create a duplicate card rather than being a no-op.

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, cost, and return shape are front-loaded in two short sentences, then the auth block. The auth paragraph is long and largely boilerplate, but it is genuinely necessary setup information rather than filler.

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 an output schema present and 90% schema coverage, the description covers the two things structured data can't: authentication and credit cost. For a 10-parameter, nested-object mutation tool, the only missing piece an agent would want is what happens on a stale or missing 'revision'.

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 90%, so the schema already documents url, title, caption, position, revision, and source. The description only adds the constraint that the URL must be public https and where it typically comes from; it adds nothing about the 'kind' enum, the optional 'source' provenance object, or revision conflict behavior.

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 and resource ('Add an image or video card to a board') plus the accepted input form (public https URL), which cleanly separates it from add_text_card, add_generation_card, and add_frame. It even names the upstream producers of that URL (import_asset result, generation's video_url, ad's video_url), so an agent knows exactly which artifact this tool consumes.

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?

Clear about the condition for use — a public https URL from one of three named sources — and adds a cost signal ('Costs no credits') that helps an agent pick this over a paid generation route. It never states exclusions, e.g. that non-https or private URLs are rejected or when add_generation_card should be preferred over re-adding a generation's video_url.

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