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

With no annotations, the description carries the full burden and does so well: it discloses the non-obvious behavior that the new card is not blank (first three cards inherit template sample texts and phone placement, later cards copy every layer of the last card minus its phone image) and states the return value. It omits permission/error behavior, so not a 5.

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?

Three sentences, front-loaded with the core action, then the generation behavior, then the return value. Dense but each sentence adds real information; no filler or repetition.

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?

There is no output schema and no annotations, so the description must cover both behavior and returns, and it does (layer ids returned for later update/removal) plus the surprising template-copy logic. The remaining gap is the undocumented platformSetId, which is minor against the otherwise complete behavioral picture.

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 0% and the single parameter platformSetId is undocumented in the schema. The description alludes to 'the set' but never defines what platformSetId is, its format, or how to obtain a valid id, so it does not compensate for the coverage gap.

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 gives a specific verb+resource: 'Add a card to the end of a platform set,' which an agent can act on. It does not, however, reconcile the name (add_screenshot) with the term 'card,' nor distinguish itself from siblings like copy_screenshot, duplicate_screenshot, or add_platform_set. Clear purpose, weak sibling differentiation.

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 by the behavior ('add a card to the end of a platform set'), but there is no explicit when-to-use, when-not, or named alternative despite a crowded sibling set of add_*, copy_screenshot, and duplicate_screenshot. The agent must infer routing rather than being told it.

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