Get eToro instrument details

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

With no annotations provided, the description carries the transparency burden. It explicitly states 'read-only', which is a key safety trait. It does not mention error behavior or output format, but for a simple read operation this is reasonable.

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 a single, front-loaded sentence with no filler. Every word adds value, and the parenthetical 'read-only' is a useful qualifier.

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?

This is a simple tool with one documented parameter and no output schema. The description explains what it does and its safe nature, which is sufficient for an agent to select it. It could mention the output structure but that is not necessary for basic selection.

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 schema already fully describes the parameter (list of eToro instrument IDs) with 100% coverage, so the description adds little beyond restating 'one or more'. Baseline 3 is appropriate since the schema does the heavy lifting.

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 uses the specific verb 'Fetches' and clearly identifies the resource as display metadata (name, type, exchange, etc.) for instrument IDs. This distinguishes it from siblings like etoro_search_instrument (which finds instruments) and portfolio-related tools.

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 phrase 'for one or more instrument IDs' clearly implies use when you already have IDs and need display metadata. It does not explicitly name alternatives (e.g., search when you lack IDs), but the context is clear enough for differentiation.

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