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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds domain behavior not present in structured fields: that futures entries are CFDs tracking CME/Eurex contracts and that orders must go through the user's own platform. Return shape is only sketched (display name, category) and pagination/ordering is 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?

Front-loaded with purpose and return fields in the first sentence, with the filter and futures caveat following in descending importance. Three sentences with little waste, though the futures/CFD explainer is arguably domain trivia that could live in a related trading tool.

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 single optional-param read-only lister with annotations covering safety and no output schema, the description says what comes back and what filtering is possible. What an agent still doesn't know — ordering, whether results are large enough to need paging — is minor for this tool class.

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 parameter's description already lists the exact category values, so the description merely repeats 'forex, commodities, indices, futures, crypto'. No format, casing, or default behavior is added beyond the schema, so the baseline 3 applies.

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 ('List all available trading symbols') and even names the returned fields (display name, category), making the resource unmistakable versus siblings like list_timeframes or get_quote. It doesn't explicitly contrast itself with any sibling, which keeps it from a 5.

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 futures note ('use them for charts and backtests; orders go through the user's own platform') is real usage guidance for one category, and the optional category filter is described. However, there is no explicit when-to-use framing relative to alternatives (e.g., calling this before backtest_strategy or execute_trade to resolve symbol names), so routing is only implied.

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