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

The description adds important behavioral context beyond the annotations: it states every call inserts a new record (does not upsert by name) and requires playbooks:write or full permission. This goes beyond the bare annotations (e.g., idempotentHint=false) by explaining exactly what that means in operation. Minor gap: does not explain what happens to existing playbook containers or return behavior, but the provided details are genuinely useful.

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 sentences, front-loaded with the core action and resource, followed by non-upsert behavior and an alternative tool recommendation. No filler or redundancy; every sentence 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?

Despite 8 parameters, nested objects, and no output schema, the description gives enough operational context: creation semantics, auth requirement, and when to use an alternative. It doesn't describe the returned value or error/edge-case behavior, which could be slightly richer, but it is largely complete for this tool's complexity and available schema info.

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?

Param descriptions cover all 8 fields (100% schema coverage), so the description does not need to repeat them. It adds a slight conceptual frame by describing the container's purpose, but no parameter-specific enrichment beyond the schema. This is acceptable for a tool with excellent schema documentation.

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 uses a specific verb and resource ('Create a new playbook container') and specifies the container's role ('for a singleton persona, skills, and memory'). It clearly distinguishes from update_playbook, and the explicit 'each call inserts a new playbook; it does not upsert by name' makes the create-only scope unambiguous.

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 gives explicit when-to-use and when-not-to-use guidance: 'Create a new playbook...' plus 'Use update_playbook to change an existing playbook, not this tool.' It also notes the required permission, helping the agent decide if the tool is appropriate for the current context.

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