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

No annotations are provided, so the description carries the full burden. For a 43-parameter mutation tool it says nothing about permission requirements, whether omitted fields are left untouched (partial update semantics), reversibility (undo is a sibling), or what is returned. Only the imageUrl/device routing is disclosed.

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 scope and then the cross-tool dependencies; no filler. It is impressively compact for a 43-parameter tool, though the field-category list is dense enough to read as a run-on.

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 43 parameters, no annotations, and no output schema, the description covers only the headline categories and two integration points. It leaves the agent without guidance on partial-update behavior, defaults, or the many undocumented visual parameters, which is not enough for a mutation tool of this size.

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 30% across 43 parameters, so the description must compensate and it only partially does: it groups the sprawl into categories and clarifies imageUrl (the app screen inside the phone, populated via upload_image) and deviceId's relationship to set_device. Dozens of color, shadow, focus-overlay, and pattern parameters remain unexplained in both schema and description.

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 and resource ('Update a card and its main phone') and enumerates the categories of changeable state: background, phone placement and app screen, pattern, fade, shadow. It does not explicitly distinguish itself from the close sibling update_phone, so an agent must infer the boundary.

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?

Provides helpful workflow routing for two fields: imageUrl must come from upload_image with type screenshot, and the phone model follows set_device. However, it never says when to call update_screenshot versus update_phone, add_screenshot, or duplicate_screenshot, and gives no exclusions or prerequisites.

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