update_metadata

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

With no annotations, the description carries full behavioral burden. It clearly states the tool preserves the body and lists the affected fields (type, level, sign, etc.). However, it does not mention error conditions or permissions, which are minor omissions for a focused update 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 two sentences, front-loaded with the core action and constraint. Every word contributes meaning; there is no redundancy or unnecessary detail.

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 update tool with two parameters and no output schema, the description is complete. It explains the tool's effect (preserving body) and lists the fields, which is sufficient for an agent to use it correctly.

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%, but the description adds context: 'preserve the existing body' and lists the metadata fields that can be updated. This adds value beyond the schema, which only names path and metadata generically.

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 purpose: 'Update only YAML frontmatter for an existing note and preserve the Markdown body exactly.' It specifies the verb (update), resource (YAML frontmatter), and constraint (preserve body), differentiating it from siblings like write_file which would modify content.

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 explicitly recommends using this tool for 'safe changes' to metadata fields when content must not be touched. It implies the alternative (use write_file for content changes) but does not name it directly. Still, the guidance is clear and actionable.

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