wayback_lookup

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

The description adds significant behavioral context beyond annotations: rate limits, status handling (including that 'total_snapshots' is omitted on failure, not zero), warnings array content, and known heavy domains that time out. No contradiction with annotations (readOnlyHint, idempotentHint).

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 well-structured: purpose first, then usage guidelines, then behavioral details. While slightly long, every sentence adds value and the information is front-loaded. Minor redundancy could be trimmed.

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 single-parameter tool with an output schema, the description covers return fields, error handling (CDX error codes), rate limits, and edge cases (heavy domains). It provides complete context for an agent to decide usage and interpret results.

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% and the schema description already clarifies the 'domain' parameter with examples. The tool description does not add additional semantics beyond what the schema provides, so a baseline score of 3 is appropriate.

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 the tool retrieves Wayback Machine snapshots for a domain, specifying key outputs (first capture, latest, total count, snapshot list). It distinguishes itself from sibling tool 'domain_report' by noting its narrower focus.

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?

Explicitly states usage for investigating domain history/age, contrasts with 'full audit use domain_report', details rate limits (100/hr free, 1000/hr Pro), and gives precise instructions for handling status='unavailable' vs 'ok'. This provides comprehensive when-to-use and when-not-to guidance.

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