position

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

Annotations already mark this as read-only, and the description adds substantial behavioral detail beyond that: `holding: null` is a normal non-error result, paper mode reads a local ledger rather than the brokerage, the response may indicate 'PAPER ACCOUNT', and the endpoint is flagged as pending verification. This tells the agent how to interpret the result and what caveats to relay, which is more than the annotations alone provide.

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 front-loaded with the core purpose, then covers null semantics, authentication requirements, paper-mode behavior, and verification status. Given the unusual edge cases involved, every sentence earns its place; there is no filler or repetition that could be removed without losing important guidance.

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?

With one parameter, no output schema, and annotations already indicating a safe read operation, the description covers the important contextual gaps: what the result means, what a null holding means, when authentication is and is not needed, how paper-mode results should be communicated, and the endpoint's unverified status. An agent has enough information to use the tool correctly and interpret its response accurately.

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 coverage is 100%, so the schema already documents `symbol` as an IDX ticker with the example BBRI. The description adds the conceptual context that the tool is specifically about one symbol's position, but it does not add meaningful parameter-level details beyond what the schema already provides. The baseline of 3 is appropriate.

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 opens with a precise statement: it reports one symbol's position — quantity held, average price, and current value. It also distinguishes itself from the sibling `portfolio` tool by noting it is cheaper for single-stock questions, so an agent can tell them apart immediately.

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 explicitly says when to use this tool ('when the question is about a single stock') and names the alternative (`portfolio`). It also gives clear conditional guidance: live mode requires a trading session, while paper mode reads a local ledger and requires no session or PIN, with an explicit instruction not to send the user to a terminal. This leaves no ambiguity about the invocation context.

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