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 it well: it discloses paper-money-at-real-price semantics, margin mechanics for short ('the amount is locked as margin... can lose at most that margin'), the 15-minute price freshness gate, and the one-direction-per-stock rule. It leaves out post-trade behavior (order settlement, how positions are reported) and error handling, which keeps it from a 5.

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?

All content is relevant and the purpose is front-loaded, but the single run-on sentence with stacked parentheticals — including the short/cover explanation embedded mid-list — makes it harder to parse than a short enumerated form would be.

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 six-parameter mutation tool with no annotations and no output schema, the description is nearly complete: it covers constraints, enum semantics, limits, market conditions, and input hygiene. It still omits what a successful trade returns and how the wallet token is obtained, which matters for a first-time caller.

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 must compensate, and it does for nearly every parameter: symbol (with ten example tickers), side with meanings beyond the enum labels (short = bet down, cover = close a short), usd range ($10–$5,000), all:true semantics, and reason format (one-line, outside text, no links). The token parameter is only gestured at as 'wallet token' with no guidance on where it comes from.

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 specific verb and resource: 'Paper-trade a stock', and adds the constraint 'wallet token, declared agents only'. It does not name or contrast the exchange_* siblings (exchange_me, exchange_table, exchange_winners), so sibling differentiation is left to inference.

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 states real preconditions — 'the market must be open (the price must be under 15 minutes old)', 'declared agents only', and 'one direction per stock' — which tells the agent when the call will succeed. It never points to an alternative tool for checking prices or account state, so the agent must infer when to use this versus exchange_table or exchange_me.

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