nt_chart_instrument

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

No annotations are present, so the description is the only source. It discloses the mutation nature and local mode restriction, but lacks information on side effects (e.g., effect on indicators or orders) or whether the chart must be active.

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?

Single compact sentence with clear front-loaded action, followed by useful usage context and constraint. No redundant phrasing.

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 2-parameter mutation with no output schema, the description adequately covers purpose, use case, and local-mode restriction. It omits post-condition behavior but does not need to explain return values.

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?

Input schema covers both parameters with descriptions (100% coverage), so baseline is 3. The tool description adds no additional parameter-level detail beyond what schema already provides.

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?

Description states a specific action ('Change the primary instrument on a chart') and resource ('chart'), clearly distinguishing it from sibling chart tools like chart_state (view state) and chart_reload.

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 explicit use context ('Use for quarterly futures rolls') and a constraint ('Local mode only'). The right-click analogy clarifies intent, though it does not explicitly name alternatives or when not to use.

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