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

The annotations already declare destructiveHint=true and idempotentHint=true, and the description earns credit by explaining what those mean concretely: the sync mirrors membership so people not in the audience are removed from the destination, and a repeat call returns status 'skipped' which counts as success. It also notes the connection result is returned. It does not cover permission requirements or failure modes beyond the already-connected case.

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?

Front-loaded with what the tool does, then prerequisite, then required inputs, then behavioral notes, then return semantics — a sensible order. A few clauses duplicate what the schema already says (the schedule enum, the parameter inventory), which is the only waste.

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 destructive, idempotent mutation with no output schema, the description covers purpose, prerequisite call, required inputs, cadence, the membership-mirroring side effect, and the success-shaped 'skipped' response. Nothing an agent needs before invoking it is missing.

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 83%, so the schema already carries most of the parameter meaning, including the full enum semantics for schedule and the mappingGuidance/fk-check guidance for audience_id_on_destination and identifier_mappings. The description mostly restates the required-parameter list and the hourly/daily/manual enum, adding little beyond the structured fields.

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 ('Creates a connection between an existing ... audience and an activation-capable destination') and pins the scope to Data Graph audiences, which cleanly separates it from connect_transformation_destination and the read-only get_/list_ siblings.

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?

'Call get_audience_destination_schema first' gives an explicit prerequisite ordering, and the required inputs (audience ID, destination ID, destination-side audience ID, identifier mappings) describe the preconditions for a valid call. It stops short of naming an alternative tool or a when-not-to-use condition, so it is clear context rather than full routing guidance.

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