get_balance

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

With no annotations, the description carries the full burden and does so exceptionally: it explains that derived fields can be `null` with a companion `<field>_error`, that `null` means UNKNOWN not zero, that `leverage` is always null for a named reason, and that `funding_paid` is exempt from that rule and is paid-positive. It also discloses the auth requirement.

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 deprecation notice is front-loaded and every sentence adds behavioral value, but the null/`_error` discussion is dense and long. It earns its length through genuine edge-case detail rather than padding.

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 no output schema, the description must describe return semantics, and it covers the key fields, their null/error behavior, and sign conventions well. It does not describe the overall response envelope, so an agent still has a small gap about shape.

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 to disambiguate and the baseline is 4. The description correctly adds no redundant parameter text.

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 gives a specific verb and resource ('Get the authenticated account snapshot: collateral balance, equity, and positions') and names its successor tool `fetch_balance`, so an agent can route away from it. It stops short of distinguishing itself from the many other account-state siblings (`fetch_account_state`, `get_account_summary`, `fetch_positions`), so it is clear but not fully differentiated.

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 front-loads 'Deprecated: use `fetch_balance`', giving an explicit alternative, and states the prerequisite 'Requires API credentials'. What is missing is positive guidance on when this legacy tool would still be the right call.

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