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

Annotations already declare it is a non-destructive, idempotent write. The description goes beyond them with cost/quota behavior ('Instant, free, no quota, no limit') and the 'not_found' failure mode for matches not owned by the current user. It stops short of stating the reverse operation (undo_radar_match) or any auth/permission detail beyond the owner check.

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 tight sentences: effect, cost contrast, and exclusion/alternative. The most decision-relevant facts (what it does, that it costs nothing, what it is not) are front-loaded with zero 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 return values need no explanation, and the description still supplies the noteworthy error case plus side effects. The only gap is reversibility — it does not point at undo_radar_match, which an agent may want after a mis-save.

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?

The description never mentions match_id, so it adds no parameter meaning. The nested schema does document match_id as 'as returned by get_radar_matches', which keeps this at a baseline 3 rather than lower, but the prose contributes nothing on parameters.

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+resource ('Save a radar match') plus the two concrete effects — keeps it in the user's list and teaches the radar ranking. It explicitly names the sibling it is not (analyze_radar_match), so an agent can route without opening either schema.

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 the exact selection condition: use this when the user likes a match; use analyze_radar_match when the vacancy itself needs analysis. The cost framing ('no quota, no limit' vs 'spends one vacancy analysis') makes the trade-off unambiguous.

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