Update screen

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

Annotations already indicate destructiveHint=true and idempotentHint=false. The description adds meaningful context by stating that the original HTML cannot be retrieved and that this is always a full content replacement, making the destructive nature concrete. It also instructs reading the authoring doc, which sets expectations for format. This goes beyond the structured hints.

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?

Two concise sentences, front-loaded with the core purpose. The first sentence states exactly what the tool does; the second adds essential caveats. 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?

The description covers the crucial behavioral context: full replacement, irreversibility (original not retrievable), and a prerequisite. Given the tool has no output schema and moderate complexity, this is reasonably complete. It doesn't address error conditions or return values, but that's partially offset by annotations and the clear replacement semantics.

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 25% (only the 'mode' parameter has a description). The description does not explain screen_id, label, or html parameters beyond implying 'complete Framework HTML document' for html. It adds minimal value to parameter understanding, and with low coverage, it fails to compensate for undocumented parameters.

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 clearly states the action ('Replace'), the target ('an existing Terminus screen'), and the input ('a complete Framework HTML document'). It distinguishes itself from create_screen by explicitly saying 'existing' and from other sibling tools by focusing on replacement. The verb is specific and unambiguous.

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?

It provides an explicit prerequisite ('Read terminus:screen-authoring first') and a key condition for use ('Original HTML cannot be retrieved, so this is always a full content replacement'). While it doesn't explicitly contrast with alternatives like create_screen, the context of 'existing' screen and the emphasis on full replacement gives clear usage direction.

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