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

Annotations cover the safety profile (non-read-only, open-world, non-idempotent, non-destructive), and the description adds genuinely new behavioral facts: the prior revision is preserved, behavior metadata is revalidated, and hard input limits apply. It still does not say what happens on validation failure or whether the call consumes the referenced revisionId.

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 compact clauses, front-loaded with the primary action and followed by side effects and limits; every phrase carries information. 'Free' is a marginal inclusion but does convey no-cost invocation.

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?

For a mutation tool with no output schema, the description covers the main effects and input limits, which is the minimum viable set. It omits ownership/permission expectations (the schema only hints 'Owned'), failure behavior, and what the caller sees after revalidation, leaving real gaps for a write operation.

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 only 50%: revisionId and imageBase64 carry no schema descriptions, and the description adds nothing about either — it does not explain whether revisionId targets the revision being replaced or the new base, nor what encoding/format imageBase64 expects. The size constraints loosely map to imageBase64 but without stating the field.

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 states a specific verb and resource: saving a locally edited PNG for a UI component, plus secondary effects (revalidate metadata, preserve prior revision). It distinguishes scope from the sibling revise_ui_pack_png by targeting a single component, but it never names that sibling explicitly, so the agent must infer the boundary from the tool name alone.

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 only implied: the agent can infer this is for pushing a locally edited PNG back, and hard constraints (4 MB, 2048 px, no SVG) narrow applicability. There is no explicit when-to-use, when-not-to-use, or routing to revise_ui_pack_png or import_asset_image.

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