Dashboards: add chart

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond them: non-destructive semantics ('Everything else on the dashboard stays as it was') and default behaviors for title and widget placement. Only the return value is thin ('Returns JSON'), which limits it from 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?

Four tight sentences, front-loaded with the core action, then defaults, then the routing guidance. No filler; each sentence adds a distinct, useful fact.

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 non-destructive additive mutation with full annotations and no output schema, the definition covers action, non-destructiveness, defaults, prerequisites, and the sibling to avoid. 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 100%, so the baseline is 3, but the description adds interpretation beyond the per-parameter schema: it explains that title defaults to the chart's name and that position/placement is governed collectively by column, row, width and height on a 12-column grid, and defaults to after existing widgets when none are given. This exceeds what each isolated schema entry conveys.

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 and resource ('Add a chart to a dashboard as a new widget') and immediately distinguishes itself from siblings by naming `charts_create` (prerequisite) and `dashboards_update` (the wrong tool, since it replaces every widget). An agent can tell it apart from other dashboard tools without opening schemas.

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?

Explicit when-to-use ('This is how a saved chart gets onto a dashboard'), an ordering prerequisite ('Create the chart first with `charts_create`'), and an explicit when-not-to-use with reason ('avoid `dashboards_update` for this, as it replaces every widget'). Nothing is left to inference.

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