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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds critical behavioral detail: bars are not returned, only a handle and summary, and the tool defaults to the chart's instrument. This goes beyond what annotations provide and helps the agent understand the tool's unique contract.

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?

Two concise sentences with no fluff. The key behavior (handle vs bars) is front-loaded, and the default behavior is stated at the end. Every word 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 has 6 parameters (all optional) and no output schema, but the description clearly explains the output (handle + summary) and the next step (pass handle to compute tools). It covers the essential workflow and default behavior. A minor gap is that the summary format is unspecified, but given the read-only nature and the handle pattern, this is sufficient for an agent to use the tool correctly.

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 83% (5 of 6 parameters have descriptions). The description adds a global 'Defaults to whatever is on the chart' statement, which clarifies that market, symbol, and possibly exchange can be omitted and will use chart context. This supplements the schema's per-field defaults (e.g., market and symbol already say 'Default: the chart') and covers exchange, which has no explicit default. The description adds value beyond the schema.

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 states a specific action: 'Load price history and return a handle to it, plus a summary.' It also clarifies that bars are deliberately not returned, which distinguishes it from tools like indicator_compute or market_derivatives that might return data directly. This is clear and actionable.

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 explains the intended workflow: pass the handle to compute tools instead of using the bars directly. It also notes the default behavior of using whatever is on the chart, which tells the agent when parameters can be omitted. However, it does not explicitly name alternative tools or state when not to use this tool, leaving a small gap.

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