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

Annotations already flag it as a non-read-only, non-destructive, non-idempotent mutation. The description adds value beyond them by disclosing that the call costs no credits and detailing the auth requirements (OAuth or Bearer API key). It still doesn't describe what happens on revision conflicts, though the schema covers the revision parameter.

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?

Front-loaded purpose followed by the alternative and the cost/auth notes. The auth sentence is long but earns its place as setup-critical information; overall tight with no 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?

Return values needn't be explained because an output schema exists, and the annotations cover the safety profile. The description adds the two things structured fields don't convey — credit cost and authentication requirements — making it complete for this mutation tool.

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 all six parameters are already documented in the schema, including defaults, the position fallback, and revision semantics. The description only supplies illustrative label examples and adds nothing new about parameters, making the baseline 3 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?

States a specific verb+resource ('Add a labelled frame') and even clarifies the resource with concrete examples ('a region such as Week 1 or Hooks'). It explicitly distinguishes itself from group_cards, so an agent can tell the two apart without opening either schema.

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?

Names the alternative explicitly for the key case: use group_cards to wrap existing cards. However, it does not address when to use add_frame relative to the other 'add_*_card' siblings (add_text_card, add_media_card, etc.), leaving that boundary to inference.

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