symbol_info

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

With no annotations, the description carries the full burden and does so reasonably: it declares 'SIDE EFFECTS: None (Read-only)' and a precondition ('Requires an active instrument loaded on chart'). It could add what happens when no instrument is loaded, but the safety and prerequisite profile is disclosed.

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 compact, front-loaded segments (purpose, when-to-use, side effects/limitations) with zero filler. Each sentence earns its place and the returned fields are packed into the opening line.

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 zero-parameter read tool with no output schema, the description covers purpose, the returned field set, usage triggers, safety profile, and a precondition — nothing an agent needs to invoke it correctly is missing.

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?

The tool takes zero parameters, which sets the baseline at 4. The description cannot add parameter meaning beyond the empty schema, and no schema gap exists to compensate for.

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 and resource ('Get comprehensive instrument metadata for the active symbol') and enumerates exactly what is returned (ticker name, exchange, instrument type, tick size, currency, market hours). This clearly separates it from symbol_search, which finds symbols rather than describing the loaded one.

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 'WHEN TO USE' clause gives concrete triggers (tick precision, pip calculation rules, exchange session times), which is more than a restatement. It does not name alternative tools explicitly, so it stops short of a 5.

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