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

No annotations are provided, so the description carries the full burden. It discloses the mutation and that an editor must be open, but says nothing about required permissions, what happens when screenshotId is invalid, whether the new layer is returned/identified, or how TextShadow/borderGroup defaults behave.

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?

A single front-loaded sentence with no filler. It is efficiently written, though it underspecifies a 19-parameter tool rather than being richly structured.

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 annotations, no output schema, 19 parameters at 32% coverage, and no sibling disambiguation, the description is far too thin for the tool's complexity. An agent can tell what it does but not how to call it correctly or what to expect back.

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?

19 parameters with only 32% schema description coverage, and the description contributes zero parameter information. Several names are non-obvious in this domain (content, align, fontWeight, the eight textShadow*/border* fields) and are undocumented in both places, so the description fails to 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?

Names a specific verb (add) and resource (text layer) plus the target context (a screenshot in the open editor), which separates it from add_div, add_asset, and add_phone. It does not explicitly distinguish itself from update_text/remove_text, but the create-vs-modify distinction is implied by the verb.

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?

Only the implicit precondition 'in the open editor' is given. There is no guidance on when to call add_text versus update_text or remove_text, no mention of prerequisites such as the screenshot existing, and no exclusions.

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