Source List Play Books

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

Despite annotations already covering the safety profile (readOnlyHint/destructiveHint), the description adds substantial context: US-only/18+ eligibility, empty result for accounts with no library, web-backend-only constraint, and the semantics of export_disabled/reason (a non-exportable title cannot be added). This is genuinely useful behavioral detail beyond structured fields.

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?

Purpose is front-loaded in the first sentence, followed by eligibility constraints and a compact field list. Every sentence carries distinct information with no filler.

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?

Coverage of eligibility rules, gating fields, and the downstream tool is strong, and an output schema exists to carry return structure. The one gap is pagination behavior for limit/offset, which is undocumented in both the schema and the description.

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 0% and the two input parameters (limit, offset) are never mentioned in the description. Since coverage is below 50%, the description should compensate by explaining pagination, but it does not — it only describes output 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?

The description opens with a specific verb+resource ('List Google Play Books eligible to be added as sources') and scopes it to purchased ebooks NotebookLM can ingest. This clearly separates it from siblings like source_list (all sources) and source_read.

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?

It establishes the context of use (finding Play Books to add) and explicitly routes the agent forward: 'pass it to source_add_play_book'. There is no explicit when-not or comparison against source_list, but the downstream linkage makes the intended workflow clear.

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