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

Annotations already declare readOnlyHint=true, and the description is consistent with that. Beyond annotations, it adds behavioral details about the return format: 'Returns dated source context; source_file and snapshot_digest are nullable when no single retained snapshot represents the response.' This informs agents about optional fields and source-dependent behavior.

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 three concise sentences: purpose, return detail, and usage guidance. It is front-loaded with the primary function and every sentence adds value with no fluff.

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 appropriately explains what is returned (provider record, exclusion/integrity context, dated source context, nullable fields). It covers the key aspects of the tool given its relatively simple parameter schema, though it could elaborate on the structure of the exclusion context.

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 parameter description in the schema already clearly defines 'npi' as the 10-digit NPI. The tool description repeats this info but adds no new semantic details (e.g., format constraints, alternative identifiers). Baseline 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 looks up a US healthcare provider by 10-digit NPI in CMS NPPES and returns provider record plus exclusion and program-integrity context. It distinguishes itself from siblings like search_providers (search by criteria) and check_exclusion (exclusion-specific) by specifying the NPI-based lookup and combined context.

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 explicit use cases: 'Use for NPI lookup, provider identity, taxonomy, practice-location, or provider due-diligence questions.' It gives clear context for when this tool is appropriate, but does not explicitly mention alternatives or when not to use it.

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