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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered. The description adds value beyond them by warning that profile fields are only present 'when known', implying partial/optional responses the agent must tolerate — a real behavioral cue not in the 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?

A single front-loaded sentence identifies the resource and identifier, a compact parenthetical lists the payload, and a closing sentence routes to the sibling. No filler.

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?

An output schema exists, so the field enumeration is partly redundant but harmless context. Nothing an agent needs in order to call it correctly is missing; only not-found/error behavior is left implicit.

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% and the schema already documents the single param with a pattern and example, so baseline is 3. The description adds that a page slug is also accepted, broadening the accepted identifier types beyond the schema's job.company.id example.

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 ('One employer by its id or page slug') and enumerates the payload (name, open jobs count, page URL, profile fields), which makes it instantly distinguishable from get_job and list_roles.

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?

Explicitly routes job lookups away from this tool: 'Use search_jobs with company_id for its jobs.' That is a genuine alternative-selection rule. It does not state failure/precondition cases (e.g., company not found), so it falls short of full 5.

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