Open positions

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond annotations: it returns the entire portfolio in one call and includes profit/loss impact from currency movement, which helps the agent understand scope and output semantics.

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 three sentences, front-loaded with the core result and fields, then use cases, then a comparative note. Every sentence earns its place: return contents, when to use, and preference over alternatives. No filler or redundancy.

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?

Despite no output schema, the description enumerates the returned fields, making the output shape clear. It also provides usage context, distinguishes from siblings, and notes the single-call portfolio behavior. This is complete for a list tool with two well-defined optional parameters.

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% for both parameters (limit and sortBy), with clear descriptions and defaults. The description does not add new parameter-level meaning but reinforces the 'whole portfolio' nature that relates to the limit parameter. Baseline 3 is appropriate because structured fields carry the semantic weight.

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 a specific verb ('Returns') and resource ('every open position in the account'), listing the exact fields returned (ticker, quantity, average buy price, current price, unrealised profit/loss). It clearly distinguishes from siblings by stating it returns the whole portfolio in one call, unlike single-position lookups.

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?

It explicitly states when to use the tool: for 'what do I hold', 'how is my portfolio doing', or any question about a specific holding when you do not already know the exact Trading 212 ticker. It also gives an exclusion by recommending it over repeated single-position lookups, which implicitly names the alternative behavior.

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