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

The description discloses behavioral traits beyond the schema: determinism, aggregate-only statistics, and privacy guarantees (no raw queries, IPs, user agents, geography). With no annotations provided, the description carries the burden, and it covers several important constraints. It doesn't mention rate limits or caching, but for a stats tool the disclosed constraints are strong.

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?

Two sentences, front-loaded with the core purpose and followed by important privacy/aggregation caveats. The caveats earn their place because they shape agent expectations. It could be slightly tighter but is appropriately sized.

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?

The tool is a simple read-only stats query with two enum parameters and no output schema. The description covers determinism, aggregate-only, provenance separation, and privacy. The main gap is lack of per-scope detail, but given the low complexity and the strong context provided, it is nearly complete.

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 50%: the period parameter is documented as 'Used by activity statistics', but scope has only enum values with no descriptions. The description clarifies that activity counts are requests, not unique agents, which adds meaning to the activity scope, but it doesn't explain what each scope value returns. Baseline 3 is appropriate: the description helps somewhat but doesn't fully compensate for the undocumented scope semantics.

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 specific resources (WagerX Agentic Index, MCP/A2A endpoint observations, machine requests) and a verb (Return statistics). It distinguishes itself from casino-focused siblings by focusing on agentic statistics. However, it doesn't explicitly name a sibling alternative, so it misses the top tier for differentiation.

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 description implies usage context: it is for deterministic aggregate statistics and explicitly contrasts with 'official provenance, editorial status and endpoint health' which remain separate. This signals when NOT to use it for authoritative data. However, it doesn't explicitly name sibling tools or lay out alternative conditions, so it falls short of a 5.

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