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

Annotations already declare readOnly, idempotent, non-destructive, and non-open-world, so the safety profile is covered. The description adds meaningful provenance context beyond that: counts are 'mirrored daily from employers' careers pages,' which tells the agent the data can be up to a day stale. It does not describe caching or rate limits.

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 that leads with the primary counts before the optional per-employer case. It is slightly run-on with the parenthetical provenance note, but no sentence 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?

With no output schema, the description carries the burden of explaining returns and does so by enumerating the count categories an agent will receive. Combined with annotations covering safety and the daily-mirror freshness note, an agent has enough to call it correctly, though the exact response shape (field names) is unspecified.

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% for the single 'company' parameter, so the schema already documents it. The description contributes only the optionality framing ('optionally one employer's open roles'), which mirrors rather than extends 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 names the specific resource (SpaceNexus jobs board) and enumerates the metrics returned: open roles, hiring employers, new-this-week and remote counts, plus an optional per-employer breakdown. It is clearly distinct from siblings like company_lookup or launch_ledger_record, though it never states the verb 'count' or 'return' 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 only implied: no-argument calls give global board counts, and passing an employer narrows to that employer's open roles. There is no explicit when-to-use vs alternatives guidance (e.g., versus company_lookup) and no exclusions or prerequisites.

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