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

Annotations already cover read-only, idempotent and non-destructive behavior, so the bar is lower; the description nevertheless adds two things the annotations do not: the auth requirement ('Agent key required') and the pricing semantics ('marked at live feed prices'), which tells the agent the numbers are live-feed valuations rather than stale snapshots.

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?

One dense, front-loaded sentence that states the resource first and the field inventory second. Every clause carries information, though the field list and auth note make it feel packed rather than trimmed.

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 correctly compensates by enumerating the returned metrics, and the parameter is schema-documented. The gap is sibling disambiguation against get_portfolio, which is the one thing an agent genuinely needs here and does not get.

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 100% and the single 'competition' parameter is fully documented in the schema, so the baseline is 3. The description never references the competition sub-book scoping and its 'unified $1M paper pool' phrasing slightly implies the default unscoped view, adding only marginal value.

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?

Names a specific verb+resource ('get_my_portfolio' / 'YOUR agent paper account snapshot') and enumerates exactly what the snapshot contains: equity, cash, market value, realized and unrealized P&L. It does not, however, distinguish itself from the sibling get_portfolio, which an agent could easily confuse with this one.

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?

No when-to-use guidance and no named alternatives. The presence of a near-identical sibling (get_portfolio) makes this omission material — the description gives no condition that tells the agent which of the two to call.

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