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

With no annotations provided, the description carries the full burden and excels: it discloses eligibility checks, pricing-dependent return shapes (evidence_documents vs. x402 handoff), tombstone behavior for deleted evidence, signed_url expiration, and the recommendation to use signed_url over file_reference. This is exceptionally transparent.

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 lengthy but logically structured: it starts with the core action, then prerequisites, then conditional return shapes, then tombstone details. The front-loading is good, but the verbosity and repetition of some details (e.g., listing available fields) prevent a perfect score.

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?

Without an output schema, the description must fully explain return values, and it does: it details the eligibility response, the evidence document structure, the x402 handoff shape, tombstones, signed_url expiration, and even agent responsibilities for retained copies. Nothing critical is missing for correct 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?

Schema description coverage is 100%, and the schema already provides a descriptive note about campaign_id (full UUID from search_campaigns, do not abbreviate). The description adds no new parameter-specific meaning beyond what the schema supplies, so the baseline 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 opens with a clear verb and resource: 'Fetch evidence documents for one campaign.' It unambiguously identifies the tool's purpose and distinguishes it from siblings like get_campaign or get_campaign_donations by focusing on evidence documents specifically for a single campaign.

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 clear context and prerequisites: it explicitly states the requirement to have accepted the Agent Operator Acknowledgement and the eligibility based on donation volume. However, it does not explicitly mention when to prefer this over alternative tools or provide exclusions for other campaign-related tools, 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.