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

Annotations indicate readOnlyHint=false and destructiveHint=false, so the agent already knows this is a safe write. The description adds useful behavioral context by clarifying the ownership scope and agent-run scoping, which is not available in the annotations or schema. No contradiction found.

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?

Two terse sentences with no filler. The primary action and resource are front-loaded, and the scoping caveat is positioned second. Every word earns its place.

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?

For a simple one-parameter mutation with annotations covering safety, the description and schema together provide enough to call the tool correctly. The digest-notification context is not expanded, but that is a minor omission given the tool's low complexity.

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 the single parameter post_ids is already fully documented as 'List of agent_social_listening IDs to mark as notified.' The tool description adds no extra parameter meaning beyond the schema, so the baseline score of 3 applies.

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 states a specific verb ('mark') and a specific resource ('social listening matches') plus the semantic outcome ('as included in a digest notification'). This clearly distinguishes it from the closely named sibling mark_monitor_events_notified by focusing on social listening matches rather than monitor events.

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 description provides an explicit scoping rule: 'Only affects posts belonging to the current user; in an agent run it scopes to the run's agent.' This functions as a when-not condition (do not use for other users' posts), but it does not name an alternative tool or explain broader selection context, so it falls slightly 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.