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

With only readOnlyHint provided, the description carries the behavioral burden and does so well: it discloses that results are grouped by strategy, that below-gate fields (delta_*, dsr, dsr_pass) are null and each null carries a reason, that empty filter cells are folded into filters_without_data, and that pagination is per-strategy with a truncated flag. It also flags the free-tier status and states filters are evaluated in isolation with no stacking.

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 purpose is front-loaded and almost every clause carries technical content, but the prose is dense, parenthetical-heavy, and long-sentenced, and the verdict category definitions repeat what the verdict enum already documents. A few statements (asset-equal-weighting, delta_ci_low/high) could be tightened without information 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?

There is no output schema, so the description must convey the return shape, and it does: envelope fields once, per-strategy baseline blocks, filter cells, filters_without_data, and the evidence block. Combined with the gating and null semantics, an agent could call and parse this correctly. Minor gaps remain around error/rate-limit behavior, which for a read-only report tool is acceptable.

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%, so the baseline is 3; the description still adds real meaning, explaining that limit/offset count strategies (not cells), that a full market is a few hundred cells, and that partial reads should be detected via the truncated flag. The verdict semantics are largely duplicated from the schema's enum description rather than extending it. Net gain over the schema is modest but genuine.

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 concrete resource (entry-filter effect reports) and a concrete analytic output (how each Pro+ entry filter affects strategy CAGR, baseline vs filtered), and its opening question gives the agent a decision to anchor on. It also implies platform-wide aggregation, which separates it from a single-strategy view. However, it never names the closely related sibling arena_get_strategy_filter_effect, so the boundary between the two 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?

Usage is implied rather than stated: the opening question plus the definition of verdict categories tells the agent what question this tool answers, and the paging note signals how to handle large markets. There is no explicit when-to-use/when-not or routing to alternatives such as arena_get_strategy_filter_effect or arena_get_strategy_performance. The agent must infer the selection rule.

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