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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows it's a safe read-only operation. The description adds the behavior of accepting multiple identifier formats (commodity id, Codex code, food name) and implies the output is a list of pesticide-limit pairs. However, it doesn't disclose whether results are sorted, paginated, or if there are edge cases (e.g., no limits found). Given annotations cover the safety profile, a 3 is appropriate as the description adds some context but not deep behavioral detail.

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, front-loaded with the action ('List every pesticide...') and the core purpose. The second sentence provides the usage context and input formats. No fluff; 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?

Given complexity is low (one parameter, no output schema, no nested objects) and annotations cover the read-only/idempotent behavior, the description is complete enough: it states purpose, input formats, and when to use. It could mention edge cases like 'returns empty if no MRLs exist' but that's minor. The purpose and usage are fully clear, so 4 is justified.

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%, so the schema already documents the 'commodity' parameter and even provides examples. The description adds the semantic meaning that the parameter can accept a commodity id, Codex code, or food name, which is also partially captured in the schema description. The description also clarifies that the parameter is interpreted as a single food (not a list). This adds value but is not a significant departure from schema, so baseline 3 is correct.

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 lists every pesticide with a Codex maximum residue limit for a given food, with the limit per pesticide. It distinguishes itself from sibling tools like codex_pesticide_mrls (which likely lists by pesticide) and codex_commodity_search (which likely searches commodities) by specifying 'in one food' and focusing on residue limits. The verb 'list' and resource are specific and unambiguous.

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 states when to use: 'Use to answer which pesticide residues are permitted in a given food and at what level.' While it doesn't explicitly say when NOT to use it or name alternative tools, the purpose is clear enough that an agent can infer it should not be used for pesticide-first queries. The sibling names provide contextual differentiation, but the description itself could be more explicit about alternatives, hence a 4 rather than 5.

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