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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=false) by disclosing sanitization behavior (scripts, event handlers, unsafe links, frames and non-text-align inline styles are stripped), a 50,000-character cap, determinism ('the text goes in exactly as given'), default placement, and the preview/confirm auth flow. These are exactly the side-effect and constraint details an agent needs before a write.

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 core action is front-loaded and every segment carries information, but the middle is one dense run-on paragraph mixing formatting vocabulary with constraints, which is harder to scan than it needs to be. It is sized appropriately for a 9-parameter tool, just not ideally structured.

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 100% schema coverage, no output schema, and annotations present, the remaining burden is behavioral context — sanitization, character limit, placement default, styling system, and the preview-then-confirm requirement — and the description supplies all of it. Nothing an agent needs to call this 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 real meaning beyond the schema: it documents the permitted styling vocabulary (data-tone, data-mark, data-size, data-callout, hr) that the bare 'text: as HTML or plain text' field does not, and reinforces that position defaults to end. It does not, however, elaborate on anchorId/width semantics beyond what the schema states.

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?

Opens with a specific verb+resource ('Add a TEXT widget — a free-text block you write yourself — to a report') and immediately names the boundaries: it is text, not a data widget, and edit_widget handles existing blocks. An agent can distinguish it from add_widget and edit_widget without opening a 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?

Explicitly routes to alternatives ('To change an existing text block call edit_widget with text; for a data widget (table, chart, KPI) call add_widget') and states the required workflow ('Requires MCP write actions; preview first, then confirm'). When-to-use, when-not, and alternatives are all present.

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