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

Annotations already cover safety profile (read-only, idempotent, non-destructive), so the bar is lower. The description adds useful behavior beyond annotations by revealing that statistics are computed from the scanner's candle buffer and are scoped to one symbol. It doesn't discuss edge cases like missing symbols, but this is acceptable given the annotations.

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?

One compact sentence front-loads the main output and scope, with the field list in parentheses. Every part earns its place; no filler or repetition of schema details.

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 two-parameter read-only tool with robust annotations, the description provides enough information: it enumerates the returned fields and scopes the tool to one scanned symbol. A slight gap is not explaining how window_hours interacts with the candle buffer or what happens when the symbol is not in the scanned universe, but the schema partially covers the latter.

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%, with both symbol and window_hours fully documented. The description does not add meaningful parameter semantics beyond what the schema already states, so it stays at the baseline for fully documented parameters.

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 exactly what the tool returns: last price and window statistics (open, high, low, close, volume, change %) for a single scanned symbol. It also distinguishes itself from broader or chart-focused siblings by noting the data is computed from the scanner's candle buffer.

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 the tool is for one scanned symbol, and the schema adds 'Must be in the scanned universe,' but it never explicitly says when to prefer this over siblings like get_market_snapshot or get_btc_chart_read. Usage context is present but left to inference.

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