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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does state that the operation 'merge's metadata and returns the updated membership, which gives some behavioral context. However, it does not mention that the operation is a mutation that may overwrite existing keys, any required permissions, or potential side effects on the membership record. Since annotations are absent, this is a moderate level of transparency at best.

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?

The description is compact and front-loaded: a one-sentence purpose, a two-sentence usage note, a return statement, and a cost hint. Each sentence earns its place; there is no redundant or filler content. The structure is easy to scan and immediately gives the agent the essential information.

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?

Given the tool's moderate complexity (5 parameters, output schema present), the description covers the key workflow: prerequisite call, how to select the instance, and the result. It does not explain output structure, but that is handled by the output schema. The only missing nuance is what 'merge' means for nested objects, but for a typical metadata update, the description is sufficiently complete for an agent to invoke the tool correctly.

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 the baseline is 3. The description adds marginal value by restating the clerk_instance_id usage (target a connection or omit for default), but this duplicates what the schema already says in the parameter description. It does not explain merge semantics for metadata objects (e.g., shallow vs deep merge) beyond the schema's 'additionalProperties: true'. Thus a middle score is appropriate.

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 first sentence uses a specific verb 'Merge' with a clear resource: 'public or private metadata on a Clerk organization membership.' This clearly distinguishes it from sibling tools like update_organization_membership (which likely updates roles/status) and update_organization_metadata or update_user_metadata, as it targets membership-specific metadata. It also scopes the operation to 'public or private metadata', leaving no ambiguity about what the tool modifies.

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?

The description explicitly instructs to call clerk.get_connected_accounts first, and explains how to target a specific connection with clerk_instance_id versus using the default account. This provides clear prerequisite context and usage direction. However, it does not explicitly mention alternatives or exclusions (e.g., when not to use this tool), so it stops short of a 5.

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