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

Annotations only declare readOnly=false and destructive=false; the description goes further by bounding the blast radius ('Touches meter metadata only — never events, never the hash chain, never billing accruals') and naming the required admin credential. It does not spell out reversibility or the effect of toggling is_test back to false, leaving a small gap.

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 operation, then the scope guarantee, then the auth prerequisite. Every sentence adds distinct information with 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?

A mutation tool with an output schema, so return values need not be described. The description covers effect scope and auth requirements well; the remaining gaps are the undocumented 'note' parameter and whether re-flagging is a no-op.

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 0%, so the description must carry all parameter meaning. It implicitly covers meter_id, the is_test flag, and names the admin token (VIRIDIS_ADMIN_TOKEN), but the 'note' parameter is never mentioned and no parameter formats are given, so compensation is partial.

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 pair (flag/unflag) and resource (a meter), plus the concrete effect: events excluded from usage statistics by default. This clearly distinguishes it from siblings like create_meter, list_meters, and record_usage.

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 'Admin:' prefix and the stated effect ('so its events are excluded from usage statistics') give clear context for when an agent should reach for this tool. It does not name alternatives or explicitly state when not to use it, so it falls short of a 5.

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