set_color_ramp_element

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

With no annotations, the description carries the full disclosure burden and does well: it warns that moving a stop past a neighbour reorders the ramp and shifts indices after the call, which is the key non-obvious side effect. It does not mention permission requirements or whether the change is undoable, leaving a small gap for a mutation tool.

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?

The purpose, the mutual-requirement constraint, and the reordering warning are front-loaded before the Args block, so the most decision-relevant information is read first. The Args/Returns sections are slightly verbose but each line earns its place.

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?

An output schema exists, so return values need not be explained (though the description still summarizes them), and the description covers scope, constraints, side effects, and all five parameters. For a five-parameter mutation with zero schema descriptions, this is complete enough to call correctly.

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 0% (only titles), so the description is the sole source of parameter meaning, and it compensates well: it defines index as zero-based, constrains position to 0.0-1.0 with an omit-to-leave-unchanged default, and states color is RGB or RGBA with the same default semantics. It does not spell out the accepted array length/format for color, so it is strong but not exhaustive.

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 opening line gives a specific verb+resource: 'Move or recolor an existing ColorRamp stop,' which clearly implies a mutation of an existing element as opposed to the sibling add/remove tools. It never names those siblings explicitly, but the word 'existing' is enough to scope it correctly.

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?

The description gives a real invocation constraint ('At least one of position or color must be given') and routes the agent to get_color_ramp when it needs certainty after reordering. It stops short of stating when-not to use it or explicitly contrasting the add/remove siblings, so it is clear context but not full when/alternatives guidance.

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