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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the description adds value beyond those hints by clarifying what an empty result actually means: nothing in the examined scope matched, consistent with openWorldHint=false. No contradiction with 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?

Two sentences, each earning its place: the first defines what the tool reports, the second warns about empty-result interpretation. No wasted words and the key usage warning is placed where it will be noticed.

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-optional-parameter, read-only tool with an output schema present, the description is complete. It covers scope selection, empty-result interpretation, and relies on the schema for parameter details.

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% — the schema already explains arxiv_id as 'One paper, or empty for the whole record store.' The description reinforces this semantic but does not add much beyond what the schema already provides.

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 identifies the resource ('sources read', 'levels run', 'stored records by tier') and the scope distinction between one paper and the whole store, making the purpose clear. It lacks an explicit command verb and never contrasts with sibling tools, so it falls short of a 5.

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?

'Call before treating an empty result as a finding' is explicit, actionable guidance for when to use this tool. It gives clear context but does not enumerate alternatives or exclusions relative to sibling tools.

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