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

With no annotations, the description carries full burden. It discloses that destination URL changes only work for dynamic types and that the physical QR code doesn't need reprinting. It also notes that isActive=false stops redirects (though this is also in schema). It could mention error behavior for invalid updates, but it covers the key operational nuances.

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, front-loaded with the core purpose. Every clause adds meaningful detail without redundancy. It is concise and well-structured for quick scanning by an agent.

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?

No output schema exists, but the description covers the essential parameters and behavioral constraints. It doesn't specify the response format or error handling, but for a simple update tool with clear semantics and no nested objects, the description is sufficiently complete for reliable invocation.

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 baseline is 3. The description adds value by explaining the type restriction for destinationUrl and the universal applicability of name/isActive. This goes beyond the schema's field-level descriptions and helps the agent understand parameter interdependencies.

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 'Update an existing QR code's properties' and enumerates specific use cases (changing destination, renaming, enabling/disabling). It clearly distinguishes from sibling tools by focusing on modification rather than creation, deletion, retrieval, or analytics.

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 provides explicit 'Use this when...' guidance and defines constraints (destination URL only for dynamic types, name/active for any type). This tells the agent exactly when to select this tool and what limitations apply, which is excellent contextual instruction.

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