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

Annotations already declare readOnlyHint and idempotentHint, covering safety. The description adds the detail that lookup is by slug or name and returns a single listing, which is mild extra context. It does not mention error behavior or return format, but the output schema exists. No contradiction with 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 a single sentence that front-loads the action and includes a concrete example. Every word contributes value, with no redundancy.

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 the presence of an output schema, annotations covering safety, and a fully documented input parameter, the description is sufficiently complete for a simple getter. It gives the source for slugs (list_erp_partners), which is helpful. Missing explicit not-found behavior, but unlikely to hinder correct invocation.

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% – the parameter is fully described as 'The partner's slug (from list_erp_partners) or its name.' The description adds an example but no new semantic meaning beyond the schema. Baseline 3 is appropriate.

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 states a specific verb ('Returns'), a clear resource ('one listing from the ERP partner directory'), and the lookup method ('by slug or name'), with an illustrative example. This clearly distinguishes it from sibling tools like list_erp_partners, which presumably returns multiple listings.

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 implies usage (single partner lookup by slug/name) but does not explicitly contrast with alternatives or state when not to use it. Sibling tools like list_erp_partners are not mentioned, so guidance is only implicit.

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