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

Annotations already declare non-readonly, non-destructive, idempotent semantics. The description adds the API-key/auth requirement and the 'in place' mutation model, which is useful. It does not say what happens to fields left unspecified or what the call returns, but with annotations covering safety this is acceptable.

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?

Two sentences, no filler, with the core action and mutable fields front-loaded ahead of the auth caveat. Every phrase 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?

For a 7-parameter mutation tool with no output schema, the description covers the action, mutable fields, and auth. It omits behavior for unchanged/unspecified fields and does not note that it only applies to resting (open) orders in the paper account context.

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 0%, so the description carries the burden and does it well: it maps price/stop-loss/take-profit/margin/leverage/trailing stop to limit_price, sl, tp, margin_usd, leverage, and trail_pct. order_id is only implied, but the field-to-parameter correspondence is largely recoverable.

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: modify a 'resting limit or stop order in place', and enumerates the mutable fields. This distinguishes it from paper_limit_order (place) and paper_cancel_order (cancel), though those siblings are not named explicitly.

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 'change a resting order in place' implies when to use it, but no alternatives are named (e.g., cancel-and-replace vs in-place edit) and there are no preconditions beyond the auth note. Usage is only implied, not spelled out.

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