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

With no annotations, the description carries the behavioral burden and does well: it discloses that the tool deliberately queries availability=all whereas get_related_products defaults to available, and that it returns a compact summary to avoid loading the full item list into context. It omits permission/auth requirements and any rate-limit or result-size caveats, which keeps it short of a 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?

Four sentences, front-loaded with what the tool returns, then usage, then a behavioral note, then the exclusion. Each sentence contributes distinct routing or behavioral value, though the availability contrast sentence could be tightened slightly.

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?

No output schema and no annotations, so the description must carry everything; it covers purpose, triggers, exclusions, and the key behavioral divergence from get_related_products. It stops short of describing what the summary's return shape contains (which count fields, how relation types are grouped), which an agent assembling a response might want.

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 67% (target and category documented, relation_type enum undocumented in schema). The description adds meaning for relation_type by referencing 'relation-type counts' and clarifies the implicit availability=all scope, but says nothing about the category slug parameter or how target accepts a model/group SKU versus an exact SKU. Modest value over the schema, so baseline 3.

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?

Names a specific verb and resource: 'Returns a compact catalog summary for related products.' It explicitly positions itself against siblings, contrasting with get_related_products' default availability scope and ruling out get_product_offer for single-SKU commercial detail.

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?

Gives concrete trigger conditions (total compatible product counts, out-of-stock consumable/accessory counts, relation-type counts) and an explicit exclusion (do not substitute for get_product_offer when one exact SKU's commercial details are needed). No alternative routing is left to inference.

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