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

Annotations already establish that this is a non-destructive in-world mutation operation, so the safety bar is partly met. The description adds no behavioral detail beyond that: it doesn't say whether omitted fields are preserved, whether the marker must already exist, or what happens on an invalid markerId. It also omits that the tool resizes markers via duration, which the description's three verbs do not imply.

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?

A single front-loaded sentence with no filler; it is efficient. The terseness borders on under-specification, but nothing is wasted or buried.

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 six-parameter mutation tool with 17% schema coverage and no output schema, the description is far too thin. Missing: partial-update semantics, markerId precedence, duration behavior, and confirmation of what the operation returns.

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 coverage is only 17% (just projectId), so the description must carry weight. It does partially map verbs to parameters — move to time, rename to label, recolour to color — which is real value beyond the bare schema. But duration, markerId, and the color enum usage are left entirely unexplained.

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 concrete verb set (move, rename, recolour) against a specific resource (marker), which distinguishes it from add_marker and remove_markers. It stops short of naming the sibling tools or defining scope, but an agent can tell what the tool does.

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?

There is no when-to-use or when-not-to-use guidance. The description never says to prefer this over add_marker for creating a marker, nor that it only modifies existing markers, and it states no prerequisites such as needing an open project or a valid markerId.

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