get_positions

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

With no annotations, the description carries the full behavioral burden and does so thoroughly: it discloses auth requirements, the mirrored-state derivation of `notional_value`/`margin_used`/`roe`/`max_leverage`/`leverage`, the `<field>_error` companion convention, the specific always-null `leverage` case, the pitfall of inferring leverage from `margin_used`, and the paid-positive sign convention for `funding_paid`. This is exactly the kind of non-obvious context structured fields cannot convey.

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?

Front-loaded with the deprecation notice, then dense but purposeful sentences about null semantics. Slightly long and clause-heavy, but with no output schema every sentence about return shape earns its place.

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?

No output schema exists, so the description must document return semantics itself — and it does, covering null/error handling, sign conventions, and auth. For a zero-param read tool, nothing an agent needs in order to interpret the response 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, so there is nothing for the description to disambiguate; baseline 4 applies. The description instead spends its space on return-value semantics, which is the correct tradeoff.

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resource ('Get the authenticated account's open positions') and immediately distinguishes itself from the sibling it is superseded by ('Deprecated: use `fetch_positions`'). An agent knows both what it does and that it should prefer another tool.

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?

Explicitly declares the tool deprecated and names the replacement (`fetch_positions`), which is the clearest possible when-not-to-use signal plus alternative. The authentication requirement is also stated up front.

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