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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuine behavioral context beyond them: the record is returned whole ('every field the catalog has for it') with the field list spelled out, which matters because there is no output schema. It does not say what happens on an unknown slug (error vs empty), which keeps it below 5.

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?

Two sentences, zero filler: the return contract first, the prerequisite second. Nothing repeated from the title or name.

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 field enumeration does the work of describing the return value, and annotations cover safety. The only meaningful omission for a single-parameter lookup is not-found/miss behavior, which an agent would reasonably want to know.

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 0%, so the description has to carry the parameter. It identifies the input as a slug and — more usefully — says where slugs come from (search_catalog), clarifying the expected identifier format and provenance beyond the bare string type in 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 and resource ('Return one catalog entry by slug') and immediately enumerates the payload fields, so it is unambiguously distinct from search_catalog (many results) and compare_entries (multi-entry diff). An agent can pick this tool without opening the 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?

'Get slugs from search_catalog' explicitly names the sibling that produces the required input and the ordering of calls, which is the main usage question here. It stops short of stating when not to use it (e.g. when several entries are needed, use compare_entries), so no explicit exclusion.

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