untag_resource

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

The description clearly indicates the mutation: removing tags from a key. However, with no annotations present, it does not disclose potential side effects, authorization requirements, idempotency, or error behavior. It covers the core behavior but leaves some operational context unstated.

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 compact and front-loaded with the usage trigger, followed by a direct action statement and a short Args block. Every sentence contributes useful information, with no wasted text.

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 two-parameter mutation tool, the description plus input schema provides enough information to call the tool correctly. It does not describe the response format or edge cases, but the operation is straightforward and the absence of an output schema reduces that burden.

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 0%, so the description must compensate. It provides concise meanings for both parameters: resource_arn is the key ARN and tag_keys is the list of tag key names to remove. This is sufficient for basic invocation, though ARN format details are not specified.

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 explicitly states the action: 'Remove tags from an APC key' and frames it with a clear trigger ('when removing stale or incorrect tags'). It clearly distinguishes itself from the sibling tag_resource, which adds tags rather than removes them.

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 first sentence provides direct guidance on when to call the tool: 'Call this when removing stale or incorrect tags from a key.' It does not explicitly name alternatives or exclusions, but the purpose and sibling context make the usage clear.

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