card_custom_field_set

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

With no annotations, the description carries the disclosure burden, and it does state the key behavioral trait that this overwrites an existing value ('set or replace'). It leaves unstated permission requirements, what happens if the field isn't attached to the card's board, and error semantics for mismatched values.

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?

Two tight sentences: the core action and the replace semantics come first, followed by the three tool-routing pointers. No restated name, no filler.

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 an 8-parameter mutation tool with rich enum/schema descriptions and no output schema, the definition covers the main risks: value replacement and how to obtain a valid type. It could go further on failure modes and on whether the field definition must already be attached to the card.

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 baseline is 3; the description earns an extra point by explaining how the type parameter is derived (from the existing definition via custom_field_get), which is workflow guidance the schema alone does not supply. It still adds nothing about cardId formats or the date string constraint beyond the schema.

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 uses a specific verb pair ('set or replace') on a precisely scoped resource ('one card custom field value'), and implicitly distinguishes itself from the sibling tools it names (card_custom_field_clear, custom_field_options). An agent can tell exactly what this does without opening the schema.

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?

It explicitly routes the agent to custom_field_get for the required type, to custom_field_options for list option ids, and to card_custom_field_clear when the intent is removal rather than setting. That is a named alternative plus the preconditions for using it correctly.

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