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

Annotations already establish readOnly/idempotent/non-destructive, so the bar for this dimension is lower. The description adds valuable behavioral context: detection is 'HEURISTIC' with 'conservative default thresholds', and returns are structured with pattern/date/direction/barIndex. This goes beyond the annotation safety profile, though it does not cover error behaviors or data source specifics.

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 two sentences with no filler; it packs pattern list, return shape, and a caveat. Every clause earns its place and the core purpose 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?

Given the simplicity (2 params, no output schema), the description covers the essential return contract by listing pattern, date, direction, and barIndex. It also flags heuristic behavior and research-only purpose, so an agent has enough to decide whether this tool fits. Minor omissions like empty-result behavior and exact barIndex definition prevent a 5.

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 100%, so the schema fully documents symbol and lookback_days. The description adds no parameter-level meaning beyond what the schema already provides; the mention of 'recent daily bars' simply echoes the trailing-days concept in 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 specifies a clear verb ('Detect'), resource ('candlestick patterns on a ticker's recent daily bars'), and enumerates the exact patterns detected. It is specific, but does not explicitly compare itself to sibling tools like stock_history or support_resistance_levels, so it misses the sibling-differentiation element for a 5.

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 implies its use for candlestick pattern detection and includes a research-only caveat, but it does not provide explicit when-to-use/when-not-to-use guidance or name alternative tools for related analysis (e.g., stock_history for raw bars, support_resistance_levels for levels). The 'for research, not investment advice' note is a limitation, not a routing instruction.

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