snapshot

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

With no annotations, the description carries the full behavioral disclosure burden. It transparently states that a surface that cannot be read is recorded as an error in place rather than omitted, and it reveals that the tool writes timestamped documents on disk while labeling itself read-only. It does not cover authentication or rate limits, but the error-in-place and file-writing traits are the key behavioral disclosures and they are present.

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 dense but not padded: the first sentence establishes the composite scope, the second excludes whole data families, and the third covers error handling plus the sibling comparison tool and the read-only trait. Each sentence earns its place, though the third sentence is slightly run-on and packs two somewhat unrelated facts together.

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?

For a 9-parameter tool with no required parameters, an output schema, and full schema descriptions, the description covers what is captured, what is excluded, how failures are handled, and how to compare with previous snapshots. It does not offer a typical use case or explicit guidance to use single-surface siblings when only one surface is needed, but the combination of description, schema, and output schema is largely 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 coverage is 100%, so the baseline is 3, but the description adds meaning by mapping each parameter array to a surface: properties to Search Console totals/top rows, apps to App Store listings, packages to Google Play installs/traffic, and slugs to WordPress.org stats. This contextualizes the 9 parameters beyond their individual schema descriptions. It does not restate defaults or constraints, which the schema already covers.

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 the verb ('Capture') and a clear resource ('four surfaces in one timestamped document'), then enumerates exactly which surfaces are included: Search Console totals and top rows per property, App Store listings, Google Play installs/traffic, and WordPress.org stats. It also explicitly lists excluded data families (Core Web Vitals, Android vitals, App Store sales and reviews), which distinguishes it sharply from siblings like crus_field_data, play_vitals, and app_store_sales.

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 communicates when to use the tool by enumerating the four surfaces and explicitly stating what it does not capture, which lets an agent route to dedicated siblings for excluded data. It also points to list_snapshots for comparing against earlier documents. It does not explicitly name alternative single-surface tools for each included category, so the guidance is clear but not fully exhaustive.

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