Append Block

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

Annotations already declare the write profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=true), so the description is not required to restate safety. But it adds almost nothing behavioral: it name-drops "strict validation" without saying what strict rejects or that it defaults to true, gives no hint that appends are non-idempotent and can duplicate blocks, and says nothing about revision checks or the failure modes the 40-param surface implies.

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?

A single front-loaded sentence with no padding, so nothing is wasted. The parenthetical is slightly vague filler, but the text is compact and the primary action leads.

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 40-parameter mutation tool with nested objects, edgeless-canvas geometry, and many overlapping siblings, one sentence is far short of complete: an agent gets no routing guidance, no sense of the edgeless-vs-document distinction, and no warning about strict-mode rejections. An output schema does exist, so return values need not be described, but the selection and behavioral context is largely absent.

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% and each of the 40 parameters carries substantive inline documentation, so the baseline of 3 applies. The description contributes only the high-level notion of canonical types/legacy aliases, placement, and strict validation; it adds no semantics for any individual parameter beyond what the schema already 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?

The verb+resource pair ("Append document blocks") is unambiguous and the parenthetical adds that canonical types, legacy aliases, placement, and strict validation are involved. It never distinguishes itself from nearby siblings such as append_markdown, append_semantic_section, add_surface_element, or create_doc_from_markdown, so an agent must infer the boundary.

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?

There is no statement of when to reach for this tool versus the many alternative append/insert tools in the sibling list. No prerequisites, no exclusions, no note about document mode vs edgeless canvas, which the schema clearly supports.

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