card_custom_field_clear

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

With no annotations, the description carries the full burden and does meaningful work: it discloses that the operation is value-only (definition survives) and that reversal requires an out-of-band call to card_custom_field_set, effectively flagging the mutation as not self-undoable. It omits permission requirements and response shape, which keeps it from a 5.

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 sentences, zero waste. The scope-limiting fact is front-loaded and the recovery path follows immediately; every clause 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 two-parameter mutation with a fully documented schema and no output schema, the description covers purpose, scope, and recovery. Only permission/auth context and the shape of the result are unaddressed, which is a minor gap at this complexity.

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 description coverage is 100% and both parameters are documented in the schema with accepted id/link/URL forms. The description adds no further meaning about cardId or customFieldId, so the baseline 3 applies.

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?

States a specific verb and resource ('clear one card's custom field value') and explicitly bounds the blast radius by contrasting it with deleting the board's field definition. An agent can distinguish it from card_custom_field_set and board_custom_fields without opening any 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?

The description establishes the when-to-use condition implicitly — remove a value while preserving the definition — and names the correct alternative for the reverse operation (card_custom_field_set). It stops short of stating explicit exclusions or preconditions, but the routing signal to the sibling is clear.

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