get_instrument

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety and reach profile is covered. The description adds the return content (trading status, fractional trading, option capability), but since an output schema exists this is largely redundant rather than genuinely new behavioral context.

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?

Purpose and return contents are front-loaded in two sentences, then parameters follow in a clean Args block. Slightly longer than strictly necessary given the output schema, but every line carries usable information.

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 two-parameter read tool, nothing material is missing: both parameters are documented including the enum the schema omits, the return fields are previewed, and safety semantics come from annotations plus the output schema.

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 0% and the schema declares no enum, so the description carries the full parameter burden — and does so: it gives the symbol format with an example and spells out all eight valid instrument_type values plus the EQUITY default. Without this text the agent could not supply instrument_type correctly.

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+resource ('Get details about a specific tradeable instrument') and immediately enumerates what those details are. The singular 'a specific' implicitly contrasts with the sibling get_all_instruments, letting an agent route correctly without opening either schema.

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?

Usage is implied by 'a specific instrument', but there is no explicit when-to-use, no prerequisites, and no mention of alternatives such as get_all_instruments or get_option_chain. An agent can infer intent but must guess at the boundaries.

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