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

Annotations already declare readOnlyHint=false and idempotentHint=true, and 'prevents duplicates if already connected' restates idempotency in practical terms. It adds nothing about permissions, what happens to an existing link (error vs. no-op), or whether the transformation must be published before linking.

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 short sentences, front-loaded with the action and effect, with no filler. The second sentence is slightly redundant with the idempotent annotation but is still useful to an agent reading only the description.

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 no output schema, the description should say what a successful call returns and what happens on an already-linked pair. It hints at the duplicate case but omits the return shape and the one undocumented parameter, so it is 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?

At 67% schema coverage, transformation_id and destination_id already carry 'ID from list_*' hints in the schema, and the description adds no further meaning. workspace_id is undocumented in both the schema and the description, leaving a real gap.

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 ('Link transformation to destination') plus the effect on event processing, which is clearly distinct from connect_audience_destination. It does not explicitly name the sibling it differs from, so it stops short of a 5.

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?

No when-to-use guidance, no prerequisites (existing transformation and destination IDs, workspace scope), and no comparison to connect_audience_destination. The only conditional information is the duplicate-prevention note, which is about behavior rather than when to call the tool.

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