card_attachment_add_url

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

With no annotations, the description carries the full burden, but it only discloses that local files are not uploaded. It says nothing about permissions/auth requirements, mutation side effects, what happens when setCover is true, or what is returned. The one constraint given is useful but insufficient for a write operation.

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?

One sentence, front-loaded with the usage condition and ending with the key exclusion. 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?

The schema fully covers the parameters and there is no output schema, but the tool is a mutation with zero annotations. The description could have mentioned permission needs or attachment side effects; as written it is minimally adequate rather than complete.

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%, so all four parameters are already documented in the schema. The description adds no parameter-level meaning beyond the schema, which is acceptable but not additive.

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 states a specific verb and resource ('attaching an existing public URL to a card') and explicitly distinguishes the tool from the sibling upload tool by noting it 'does not upload local files.' An agent can select this tool with no ambiguity.

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 clearly states when to use the tool ('attaching an existing public URL') and gives an exclusion ('does not upload local files'). It stops short of naming the sibling alternative (card_attachment_upload) or describing prerequisites, so it is strong but not exhaustive.

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