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

Annotations already declare the non-destructive write profile. The description goes beyond them by disclosing the auth requirement (owner only), the semantic consequence of the mutation (default routing for all payments unless overridden), and the return shape ({ connection }). It does not cover reversibility or idempotency of repeated calls.

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?

Three short sentences, front-loaded with the effect, then the permission gate, then the return. No filler or restatement of the title.

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 two-parameter mutation with full schema coverage, the description covers effect, authorization, and return value. The only gap is that no output schema exists and the '{ connection }' return is stated without describing what fields it contains.

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 both parameters are already documented, including provenance hints (connection id from workspaceConnection_list, workspaceId from workspace_list). The description adds no syntax or constraint detail beyond the schema, so the baseline 3 applies.

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 (make default) and resource (Stripe payment connection) plus the exact business effect: charges route through it unless another is named. This is clearly distinguishable from siblings like workspaceConnection_list, which only enumerates connections.

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?

Gives the key authorization prerequisite ('Workspace owner only'), which tells the agent when the call is viable. It does not name an alternative tool or an exclusion condition, but the sibling set offers no competing 'set default' operation, so the context is sufficient without being exhaustive.

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