add_to_array_field

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

With no annotations provided, the description carries the burden of behavioral disclosure. It does reveal one key behavior: 'Creates the field if it does not exist.' However, it omits other important behaviors such as error handling when the field is not an array, idempotency (duplicates ignored is only in schema, not description), and the impact of createIfMissing=false. The description is not misleading but is incomplete for a mutation tool.

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 a single, tightly written sentence that front-loads the primary action and includes a useful example. It has no redundancy or filler, earning full marks for conciseness and structure.

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?

The tool is relatively simple, and the schema documents all parameters, so the description does not need to explain return values (no output schema). However, given the absence of annotations and the existence of closely related sibling tools, the description lacks essential context about edge cases (e.g., non-array fields, failed additions when createIfMissing=false) and how this tool fits with alternatives. It is minimally complete but not thorough.

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?

Since schema description coverage is 100%, the baseline for this dimension is 3. The description adds little beyond the schema: it gives examples of field values (tags, aliases) and reiterates the create-if-missing behavior, both of which are already captured in the parameter descriptions. No additional parameter meaning is provided.

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 clearly states the tool's function: 'Add values to an array field in frontmatter (e.g., tags, aliases).' It mentions a specific resource (frontmatter array fields) and action (add values), which distinguishes it from related tools like remove_from_array_field. However, it does not explicitly name alternatives like add_tag, so it stops short of fully differentiating from all siblings.

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 implies usage context by giving examples like 'tags, aliases' and mentions the behavior of creating the field if absent. However, it does not explicitly state when to use this tool versus alternatives (e.g., add_tag, update_frontmatter) or provide exclusions. The usage guidance is therefore only implicit.

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