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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false), so the bar is lower. The description adds the important constraint that the map must contain only new nodes and points at the get_style_reference contract, but says nothing about error behavior, attachment conflicts, or what happens when parentId does not exist.

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?

Dense but front-loaded: the core action and attach point come first, followed by the node shape and then the alternatives/contract. The 'Contract:' fragment is slightly telegraphic but every sentence carries information relevant to correct invocation.

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 nested-object mutation with 7 parameters and no output schema, the description covers the payload contract and defers styling details to get_style_reference. It nonetheless omits return behavior and failure modes, leaving the agent partially informed for a structurally complex write.

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 would be 3, but the description genuinely extends the schema: it enumerates the internal node shape (type.resolvedName, isCanvas, props, parent, nodes[], linkedNodes) which the schema only summarizes as 'Flat map { nodeId: node }'. This clarification of nested-object structure is real added value.

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 subtree') and explains what constitutes the payload (flat map of new nodes plus rootNodeId). It distinguishes itself from one sibling by noting apply_kit_block covers standard sections, but leaves its relationship to insert_node/move_node/add_page unstated.

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?

Provides an implied when-not ('apply_kit_block covers standard sections') and a contract reference to get_style_reference({ topic: "editing" }), which is genuinely useful context. However, there is no explicit statement of when to choose add_nodes over the nearby insert_node, move_node, or add_page siblings.

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