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

Annotations already declare read-only, idempotent, non-destructive behavior, so safety is covered. The description adds genuinely useful context beyond them: this reads a stored snapshot rather than live-fetching, which explains staleness and latency expectations. It does not mention pagination or auth/workspace scoping nuance.

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, zero filler, with scope and the stored-vs-live distinction front-loaded. The metric enumeration earns its space by telling the agent what a call yields.

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 7 optional params and an output schema present, the description needn't explain return values, and it correctly covers scope plus the live-data exclusion. It is nearly complete; only explicit guidance on combining workspace/publicationId scoping is absent.

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%, so all 7 parameters (period, from/to, platforms, workspace, contentTypes, publicationId) are already documented with defaults, enums, and constraints. The description adds no syntax, format, or interaction detail 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 (read) and resource (stored Narrareach Stats) and enumerates the exact metric families returned. It also draws a boundary against live per-platform analytics, which cleanly separates it from sibling get_platform_analytics.

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?

Gives a clear when-not condition ("Does not live-fetch Substack or per-platform account analytics"), routing the agent to the alternative for live data. It never names the sibling tool explicitly and offers no positive 'use this when' trigger phrase, so it stops 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.