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

Annotations already declare the tool read-only, idempotent, and non-destructive, so the description does not need to cover safety. It adds context about the private R2 evidence store and the 'currently have' state, but does not describe pagination, output size limits, or other behavioral traits. This is adequate for a simple list but adds only modest value beyond annotations.

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 two sentences with no filler. The first sentence immediately states the verb, resource, and scope. The second sentence adds a clarifying caveat that prevents misinterpretation. Every clause earns its place.

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 zero-parameter, read-only list operation, the description is nearly complete: it states what is listed, where the data lives, and what it does and doesn't mean. It does not specify the exact output format (e.g., array vs. object wrapper), but 'List the source ids' strongly implies a flat list. Adequate for the tool's simplicity.

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 tool has zero parameters)Skip, so schema coverage is trivially 100%. Baseline for zero parameters is 4. The description adds semantic context about what the output represents (which sources have versioned raw snapshots), which is valuable since there is no output schema.

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 a specific verb ('List'), a specific resource ('source ids that currently have versioned raw snapshots in LiveDataLink's private R2 evidence store'), and distinguishes its scope by noting what it does not imply (normalized query tool availability). An agent can clearly understand what this tool does and how it differs from other source-related tools.

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 clearly states its purpose: 'reports hosted ingestion coverage.' It gives context for when this would be relevant (checking which sources have raw snapshots). It does not explicitly name alternative tools or exclusion conditions, but for a zero-parameter list tool, the guidance is sufficient and not misleading.

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