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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is partially covered. The description adds genuinely useful behavior: 'words' is interpreted (a named date/event defers the lead, stop-words pause it) and the refusal lands on the lead's timeline where the next run reads it — side effects an agent could not infer from the annotations.

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?

Well front-loaded with the core action and purpose, but a large share of the text is the 23-value reason_code dump, which duplicates the schema enum rather than adding meaning. The genuinely informative clause about 'words' is buried after the list.

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 mutation tool with annotations and no output schema, the description covers the key downstream effect (the refusal appears on the lead's timeline for the next run) and the dual meaning of card_id/reason_code/words. What is missing is any guidance on ordering against sibling card tools and any error/permission behavior.

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?

With only 33% schema description coverage, the description must compensate. It does so well for 'words' by explaining that free text is parsed for dates/events and stop commands, and it clarifies that reason_code is a fixed choice. The reason_code list merely restates the schema enum, and 'words' format is still not fully specified, so it stops short of 5.

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 opens with a specific verb+resource ('Refuse a card, and say why') and enumerates the required reason_code, so the operation is unambiguous. However, it never differentiates itself from close siblings like stop_a_card, set_a_card_aside, or bring_a_card_back, which an agent must choose between.

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?

Usage is only implied: an agent can infer you call this to decline a card, but there is no explicit when-to-use, no prerequisites, and no routing to alternatives such as stop_a_card or set_a_card_aside. The reason_code enumeration hints at intent but does not state when each situation applies.

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