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

Annotations declare readOnlyHint=true, and the description adds behavioral context beyond that: it states the tool does not recompute current data, which is a meaningful behavioral trait. It also implies the return includes a viz spec that can be passed to run_insight_query. The description doesn't contradict annotations. A small gap: it doesn't mention pagination or ordering, but the description already adds value beyond the annotation.

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 description is three sentences, each earning its place: the first states the core function and return fields, the second clarifies a key behavioral distinction, and the third gives concrete use cases. It is front-loaded with the most important information and has no filler.

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 simple read-only list tool with one optional parameter and no output schema, the description is nearly complete. It covers what the tool returns, what it doesn't do, and when to use it. The only minor gap is that it doesn't describe the exact structure of the 'viz spec' field, but that is likely documented elsewhere or self-explanatory given the sibling tool.

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 100%, so the schema already documents the single optional 'id' parameter. The description adds context by explaining the parameter's purpose ('fetch a single pinned insight') and the omission behavior ('Omit to list all'), which goes slightly beyond the schema's description. This is a good complement to the schema.

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 states a specific verb ('List'), a specific resource ('the user's pinned dashboard insights'), and the exact fields returned (id, title, viz spec, sort order). It also distinguishes itself from run_insight_query by explicitly saying it does not recompute current data, which differentiates it from the sibling tool.

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 explicitly says when to use this tool: 'Use this to see what's already pinned before proposing a new one, or to find an insight's id/spec to edit or rerun.' It also names the alternative (run_insight_query) and the condition for using it ('if you need fresh numbers'). This is clear, actionable guidance.

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