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

Annotations are minimal (all false hints), so the description carries the burden and it delivers: it discloses the plan widget limit as a potential failure, the mandatory :customer_id filter on customer dashboards, and required precursor calls. No contradiction with annotations — readOnlyHint=false aligns with the write nature of "Add".

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?

Three sentences with zero filler: purpose is front-loaded first, prerequisites in the second sentence, and constraints in the third. Every sentence 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?

For a tool with 8 parameters and no output schema, the description covers prerequisites, constraints, and limits well; the schema handles layout and allowSharedAcrossAllCustomers details. The one gap is that the return value (e.g., created widget id needed to chain into set_widget_layout or update_widget) is never stated, and there is no output schema to fill that void.

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 high at 88%, so the baseline is 3. The description adds genuine cross-tool semantics beyond the schema: it maps visualizationConfig to list_widget_types and query to run_query_preview, telling the agent how to correctly populate two complex 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?

"Add a chart, table or KPI to a view" uses a specific verb plus resource enumeration and names the target container. This clearly differentiates create_widget from sibling create_dashboard and create_view without needing to open the schema.

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 explicit workflow guidance: call list_widget_types for visualizationConfig keys and run_query_preview first to validate query columns. It also states when the tool applies (multi-customer dashboards require :customer_id filtering) but stops short of explicitly naming when-not alternatives such as update_widget.

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