get_post_stats

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

With no annotations, the description takes on the full burden. It discloses key behavioral traits: covers the whole archive, supports paging, and ignores any date filter. It also implies read-only behavior by 'Rank the posts'. It does not mention permissions, rate limits, or the exact response shape, but the core behaviors are well covered.

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 description is front-loaded with the verb and resource, then provides concrete usage examples. It is composed of two information-dense sentences that each earn their place. It is slightly long, but not padded, and does not waste words.

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?

Given the tool has no output schema and a moderately complex behavior (43 metrics, paging, no date filter), the description is quite complete. It explains primary use cases, the no-date-filter limitation, and the paging approach. Minor gaps like draft inclusion or exact return fields are not critical for selection and invocation.

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?

The input schema already documents all four parameters with 100% coverage, so the baseline is 3. The description adds meaningful semantic context, especially for order_by, by giving concrete examples like 'signups' for list growth and 'estimated_value' for worth, which goes beyond the schema's generic descriptions.

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 clearly states a specific action ('Rank the posts') with a clear object ('of your Substack publication') and a well-defined scope (43 per-post metrics). The focus on per-post metrics distinguishes it from siblings like get_publication_stats and get_analytics, which likely report aggregate stats.

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 provides explicit context for when to use the tool, such as identifying which posts grew the list or cost subscribers, and also gives practical guidance on the absence of a date filter, recommending sorting and paging instead. However, it doesn't explicitly name alternative tools for aggregate stats, so it stops short of a full when-to-use vs. alternatives.

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