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

Annotations declare readOnly and idempotent hints, and the description adds behavioral details beyond those, such as fuzzy case-insensitive matching, ranking by COA quality, and disclosed referral links. This enriches the agent's understanding without contradicting 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 three sentences, each providing distinct value: core purpose, output specifics, and usage examples. It is not overly verbose, but could be slightly more compact by trimming redundant qualifiers like 'vetted' and 'third-party-tested' in sequence.

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 simple tool with one parameter and no output schema, the description is complete: it explains what the tool returns, how parameters are matched, and what use cases it serves. It lacks nothing essential, though it does not elaborate on the ranking algorithm or page size, which are minor.

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 schema already describes the 'compound' parameter with examples, but the description adds interpretation guidance with "Fuzzy, case-insensitive matching" and a broader set of examples. This adds meaning beyond the schema, though the schema coverage is already high.

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 finds where to buy a peptide online from vetted vendors, with specific output details (ranked vendors, COA quality, PepScore, links). However, it does not explicitly distinguish this from sibling tools like check_vendor or list_verified_vendors, so it misses the full 5 criterion.

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 explicitly provides use cases: "where can I buy X", "best source for X", and "which peptide vendor is trusted for X". This gives clear context for when to use the tool, but it does not mention alternatives or exclusions, 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.