FocusNotebook

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

With no annotations, the description carries the full burden and does disclose the central trait: this is a state-changing operation that alters default command routing. However, it doesn't cover failure modes for invalid notebook identifiers, whether the selection persists, or how success is reported, which are meaningful gaps for a mutation tool with zero annotation coverage.

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, each with a distinct job: state the action, explain the effect and its precondition, and point to the companion tool. Zero filler, and the core action is front-loaded.

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 simple tool (1 parameter, no output schema, no annotations), the description covers the essentials: what it does, when to use it, its effect, and how to discover valid inputs. Minor omissions — error behavior and success feedback — are not critical for correct invocation, so this is slightly above adequate.

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%, and the schema already documents the notebook parameter well with format examples (URL, path like 'index' or 'voronoi', index like '0'). The description adds no parameter-level meaning beyond what the schema provides, 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 ('Focus') on a specific resource ('notebook') and explains the concrete behavioral consequence: it sets which notebook receives commands by default. This differentiates it from siblings like ListNotebooks (listing), Navigate (movement), and GetValue (reading), even without naming them explicitly.

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?

Provides a clear trigger condition ('When multiple notebooks are connected') that tells an agent when this tool is relevant, and explicitly names ListNotebooks as the companion for discovering valid targets. Stops short of a full 5 because it doesn't state when not to use it (e.g., single-notebook sessions or read-only workflows), but the context is strong.

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