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

Annotations declare destructiveHint=true and non-idempotent, and the description adds real context beyond them: read-receipt requirements for hosted edits, validation ordering ('Layout, font, device and asset validation occurs before saving'), and the null-removal semantics. It stops short of describing rollback or partial-application behavior, but the supplemental detail is solid.

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-loads the core operation, then layers in behavioral rules in short declarative sentences. Dense but each sentence carries actionable information; no obvious padding.

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?

Given an output schema exists and annotations cover the safety profile, the description supplies the remaining behavioral glue an agent needs: scope defaults, read-receipt gating, field-preservation semantics, and validation timing. Nothing critical to correct invocation is missing.

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?

With 60% schema coverage and 10 params, the description compensates meaningfully: nodeType is required, omitted nodeId matches all nodes of that type, dot-notation preserves siblings, null removes fields, formatId edits are independent of layouts, and resetFormat behavior. The atomic flag and language param don't get description-level treatment, but the core semantics are covered.

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 ('Applies scoped operations to saved screenshot layouts'), which is clear enough for an agent to distinguish it from read-only siblings like get_layout. It doesn't explicitly name when to pick it over save_layout or sync_layout, but the mutation framing is evident.

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?

'Hosted edits require a fresh same-target read receipt' and 'Defaults to mobile only' give conditional guidance. However, the description never explicitly contrasts this tool with save_layout, sync_layout, or transform_graphics, leaving the agent to infer the routing.

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