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

Annotations only declare read-only/idempotent/closed-world, but the description adds real behavioral context: deterministic lexical comparison rather than semantic review, the four verdict types with verbatim excerpts, the rule that a source without supplied text is always source-unavailable, the absence of network/model/database/history/payment I/O, and a client-side retention/privacy warning.

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?

Dense and front-loaded: the core split-bind-compare action leads, verdict/return behavior follows, and constraints and the privacy caveat are correctly placed last. Five information-packed sentences are on the long side, but each earns its place and nothing is redundant.

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?

With no output schema, the description carries the burden of explaining return values and does so (verdict types plus verbatim excerpts), while annotations cover the safety profile. For a one-parameter tool with closed-world, idempotent, read-only behavior, nothing needed to call it correctly is missing.

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 single parameter is fully documented in the schema (100% coverage), which sets a baseline of 3, but the description adds format-level meaning the schema lacks: the citation markers accepted ([3], cite{key}, [@key], Author (Year)) and the reference-list formats (BibTeX, RIS, DOI/link). That goes beyond restating the 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?

States a specific verb chain (split, bind, compare) over a precise resource (a private passage's cited claims vs supplied source text) and enumerates the exact verdict vocabulary. It is clearly distinguishable from siblings like evidence_draft or paper_lookup without opening any schema.

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?

Gives clear context for when this applies (comparing a draft's cited claims against source text the caller supplies) and implicitly rules out fetching by stating 'No fetching, model, database, history...'. It never names an alternative sibling or an explicit when-not condition, so it stops short of full routing guidance.

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