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

Annotations already declare readOnlyHint, openWorldHint and non-destructive behavior, so safety is covered; the description goes further by disclosing the returned envelope (N, Wilson 95% CI, minimum-sample guards, first/second-half stability split, per-year counts, distribution for continuous outcomes, disclaimer). The 'Historical conditional frequencies, not predictions' caveat is genuinely useful interpretive context, though it omits failure modes and any rate/availability limits.

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?

The core identity ('One precomputed session-statistics result') is front-loaded and the clause list maps to actual returned fields, so little is wasted. It is a single very dense sentence, though, and the trailing id-source sentence could be folded in without loss.

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 must carry return-value information, and it does so thoroughly, listing components of the result and a disclaiming caveat. What is missing is minor: no note on error conditions or sparse-data behavior beyond the mention of minimum-sample guards.

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% across all three parameters, including the detailed third-person 'context' wording, so the schema carries the semantics. The description only echoes the 'see edge_presets / edge_symbols' pointers already present in the schema, adding no format or syntax detail beyond 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?

The description names a specific verb-plus-resource (a precomputed session-statistics report) and pins the exact quantity returned: P(outcome | conditions) for a preset on a hosted symbol. It also implicitly separates itself from edge_presets/edge_symbols by casting them as id sources rather than result producers, so an agent can route without opening schemas.

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 tells the agent where the required ids come from ('Preset ids come from edge_presets; symbols from edge_symbols'), which is real prerequisite guidance. However, it never states when to prefer this tool over data-fetching siblings such as trackers_query or propfirms_* tools, nor any when-not condition, so usage is only implied.

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