set_custom_column

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

The description discloses behavior: it sets values, supports appending via the 'append' parameter. Since no annotations are provided, the description carries the full burden of behavioral disclosure. It explains the effect of the 'append' parameter well, but does not mention any destructive implications or error conditions beyond standard input validation.

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 concise and well-structured: a one-line summary, a usage tip, then a clear parameter list. Every sentence adds value, and there is no extraneous information.

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?

Given the tool's moderate complexity, annotations are missing, and schema coverage is 0%, the description provides adequate parameter explanations and a cross-reference to get_custom_columns. It could mention return value (since output schema exists, not required) but the description is largely complete.

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 0%, so the description must compensate. It defines each parameter: book_id (Calibre book ID), column (lookup name format with example), value (value to set), and append (explanation of behavior). This adds significant meaning beyond the schema's type-only definitions.

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 sets the value of a custom column for a book, specifying the action ('set'), resource ('custom column'), and scope ('for a book'). It distinguishes from siblings by referencing get_custom_columns() for lookup.

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 provides explicit guidance on how to reference columns via lookup name and directs to get_custom_columns() for available columns. It implies usage context but does not explicitly state when not to use this tool or provide alternative approaches beyond listing siblings.

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