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

Annotations already declare it is a non-read-only, open-world, non-idempotent, non-destructive operation. The description adds real value beyond that: PRO gating with a 403 pro_required outcome and the exact response shape {ok, subscribed, cvId}. It does not say what happens on repeat subscriptions or how to undo them, which matters given idempotentHint=false.

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?

Three short sentences, front-loaded with the action and the PRO constraint, then the trigger condition, then the return contract. No filler and nothing buried.

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 an optional-only parameter set and no output schema, the description supplies what the schema cannot: the PRO entitlement, the 403 failure mode, and the response keys. The remaining gap is lifecycle behavior — duplicate subscriptions and unsubscribing — which an agent would want before promising a side effect.

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% and both parameters are already documented, so the 3 baseline applies. The mention of matching 'one of their CVs' loosely corroborates the cvId default but adds no syntax or selection guidance beyond 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 (subscribe) and resource (weekly email of matched job openings), plus the matching basis against the user's CV. An agent can tell this is a notification-subscription operation, distinct from CV/application/job-match siblings.

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?

"Use when the user wants job alerts by email" gives an explicit triggering condition. It stops short of stating when not to use it or naming an alternative (e.g. match_takemeup_cv_to_job for one-off matching), so it falls short of a full routing rule.

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