Add section heading to Docling document

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the safety profile is known. The description adds that the tool 'inserts' a heading into an existing cached document, which is useful. However, it does not explain where the heading is inserted, whether it appends at the end, or how it interacts with existing document structure.

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 description is compact and front-loaded with the core purpose. The additional sentences clarify the cache prerequisite and heading-level semantics without unnecessary verbosity. Every sentence earns its place.

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 simple three-parameter mutation tool with an output schema and clear annotations, the description adequately covers the purpose, prerequisite, and heading-level behavior. The main missing detail is insertion position, but this is a minor gap given the tool's simplicity and the availability of structured schema information.

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 schema documents all parameters well. The description adds a small clarification that section levels represent heading hierarchy with examples like H1 and H2, but most parameter meaning is already present in the schema. This matches the baseline for high schema coverage.

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 description states a specific action and resource: 'Add a section heading to an existing document in the local document cache.' It is clear this tool modifies an existing Docling document by inserting a heading. It does not explicitly differentiate itself from sibling tools like add_title_to_docling_document, but the term 'section heading' and the concept of heading levels provide enough distinction for a clear purpose.

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?

The description clearly indicates that this tool is for documents 'already been processed and stored in the local cache,' establishing the prerequisite context. It does not explicitly name alternatives or exclusions, but the context is clear enough for an agent to know when this tool applies.

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