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

readOnlyHint=true already tells the agent this is a safe read, and the description adds nothing beyond that — no not-found/miss behavior, no mention of what fields the record contains, no side-effect or permission context. For a trivial read tool the gap is small, but the description contributes almost no behavioral value over the annotation.

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?

A single four-word sentence, front-loaded with verb and resource, with no filler. It is concise to the point of being terse, but nothing is wasted.

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 one-parameter read tool with readOnlyHint annotations and no output schema, the definition is minimally sufficient — an agent knows what to call and with what. It stops short of covering the invalid-slug/not-found case or what the response looks like, which would make it complete.

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% with a single parameter, and the schema already documents 'slug' as a product slug. The phrase 'by slug' in the description merely echoes that, adding no format, casing, or uniqueness details beyond 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?

'Get one product by slug' states a specific verb (get), resource (product), cardinality (one), and lookup key (slug). It implicitly distinguishes itself from list_products and search_products by being a single-record lookup, though it never names those siblings explicitly.

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?

Usage is implied: fetch a single product when you already have its slug. There is no explicit statement of when to prefer this over search_products (e.g. when the slug is known) or what to do when the slug is unknown, so guidance is only inferred.

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