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

Annotations already declare readOnly=false, destructive=false, openWorld=false. The description adds genuinely useful context beyond that: content 'stays editable on the board' after drawing, the ref-to-arrow wiring model, and the fact that it returns each item's id (valuable since there is no output schema). It omits any permission or rate/limit caveats, keeping it 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?

Four sentences, all substantive, with the action front-loaded in the first clause. The diagram-type enumeration is long but earns its place by aiding tool selection; nothing is redundant.

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 high-complexity tool with five oneOf item variants, a 100% documented schema, and no output schema, the description covers what it draws, post-state editability, the ref mechanism, and the return value. The main remaining gap is explicit routing against sibling creation tools.

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% (defaults, enum values, ref semantics, limits) and the two top-level parameters are documented in the schema. The description restates the ref/arrow-pointing workflow but adds no syntax or constraint detail beyond it, so the baseline 3 for a fully documented schema is appropriate.

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 verb and resource are precise ('Draw notes, text, shapes, frames and arrows on a Flett board in one call') and the enumerated item types plus diagram use-cases (flowcharts, mind maps, kanban) make the tool's remit unambiguous. However, it never names or contrasts with nearby siblings such as add_block, add_map, or set_text, so differentiation is inferred rather than stated.

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?

Usage is implied through the diagram-type list and the 'in one call' batching hint, which tells the agent this is the bulk-diagramming entry point. There is no explicit when-to-use vs when-not guidance and no alternative tool is named, so the agent must infer the boundary with add_block/add_map.

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