viewer_select

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

Annotations only give destructiveHint=true, so the description must carry the real behavioural burden — and it does, disclosing that selection uses neutral yellow/blue colours, hides nothing else, and REPLACES any previous selection (which explains the destructive hint). What it doesn't cover is whether the selection persists across reloads or what the call returns, so it stops short of a 5.

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?

Front-loaded with the core action and its visual effect, then parameter usage, then alternatives. Every sentence carries information; there is no filler or restatement of the name.

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 an output schema present, return values need not be described, and the description covers purpose, both parameters, side effects (replacement), and sibling routing. Nothing an agent needs to invoke it correctly is missing.

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 0% (bare array-of-string titles), so the description must compensate, and it does: pnt_ids is 'group A' and pnt_ids_b is an optional second group highlighted in a distinct colour. The only gap is that it never states the pnt_id string format or whether the call errors on unknown ids.

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 (highlights) plus resource (a set of elements in the open viewer) and the scope ('by pnt_id, in neutral colours... with nothing else hidden'). It explicitly distinguishes itself from viewer_highlight_clash, which is named as a sibling for a different effect.

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?

Names the concrete alternatives and the conditions that select them: viewer_list_clashes / viewer_get_properties to obtain pnt_ids, and viewer_highlight_clash for a clash pair with the model isolated. A caller knows both when to use this tool and when to route elsewhere.

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