switch_book

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

With no annotations provided, the description carries the full burden. It discloses the persistent side effect (all subsequent calls and logs operate on the new book until next switch) and the conditional availability (only when 2+ books). However, it doesn't disclose any effects on in-flight operations or whether the switch is reversible, but given it's a niche state tool with no safety annotations, the disclosure is reasonably good.

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: first sentence states the core purpose, second line covers persistent side effects, final line states availability condition. Zero wasted words, 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?

The tool is simple (single parameter, output schema present) and the availability condition plus behavior are covered. The output schema exists so return values are documented. Could mention what happens with an ambiguous or unmatched name, but the parameter description's 'Must uniquely identify' covers the constraint implicitly. Adequate for the tool's complexity.

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% — the schema thoroughly describes the 'name' parameter, including case-insensitive prefix matching, unique identification requirement, and pointer to get_server_config for the list. The description adds the behavioral scoping (state persists until next switch) but doesn't add much beyond schema for the parameter itself. Baseline 3 is appropriate since schema does the heavy lifting.

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 clearly states the verb (switch), resource (active GnuCash book), and scope (multi-book sessions only). It distinguishes this from siblings — it's the only state-changing operation that affects which book subsequent tool calls operate on, and clarifies it's only present when 2+ books are configured.

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 explains that this applies to multi-book sessions only and that all subsequent tool calls and audit/debug logs operate on the newly-selected book until the next switch. It doesn't explicitly name an alternative tool, but 'get_server_config' is referenced in the parameter description for listing books, providing directional context. An explicit 'when not to use' for single-book sessions isn't stated, though the '2+ books' condition implies it.

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