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

Adds real behavioral context beyond the annotations: paper mode moves no funds and tags positions/P&L as paper, live mode is gated, and a confirmation token is implied by the gate. Nothing here contradicts destructiveHint=true / idempotentHint=false, but error behavior, exposure limits, and reversal are unstated.

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?

Three front-loaded sentences with the credential requirement and the paper/live safety rule first, then direction semantics. The parenthetical about register_agent is slightly awkward but no sentence is wasted.

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 with no output schema, it covers the high-risk dimensions an agent needs (auth source, paper default, gating for real funds, directional payoff). Details of card_id vs card_name and the confirmation token are left to the schema, which documents them fully.

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%, so the baseline is 3, and the description earns an extra point by explaining that 'bull' profits when the index rises and 'bear' when it falls, plus that paper defaults to true. It adds interpretive meaning over the schema's terser 'bull = long the index, bear = short it'.

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 ('Open a position on an Event Card's index') scoped to 'YOUR linked platform account', which separates it from siblings like place_order and preview_card_basket. The trading direction semantics are pinned down as index-movement P&L, not generic long/short jargon.

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?

Gives the key selection condition: paper is the default and live only occurs with an explicit paper=false plus the platform trading gate, and it points at register_agent for the API key. It does not name a sibling to prefer first (e.g. backtest_event_card_idea for testing an idea), so it stops short of explicit alternatives.

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