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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation profile is covered. The description adds genuinely non-obvious behavior beyond that: marking one notificationId also marks the other notifications about the same card, mirroring in-app behavior. It does not state reversibility or auth requirements, so 4 rather than 5.

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 dense sentence with the primary behavior front-loaded and zero filler. The nested parentheticals around notificationId make it slightly harder to parse at a glance, keeping it from a 5.

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 three-optional-parameter mutation with no output schema, the description covers all invocation modes plus the important cascade side effect. Missing only secondary details such as return value and reversibility, which the annotations do not cover either.

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 the full semantic burden, and it does: it explains what each of the three parameters means and the scope it selects. It does not state that all parameters are optional or what happens if several are supplied at once, leaving a small gap.

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 ('Marks ... as read') and resource ('notifications'), and immediately enumerates the three distinct scopes the tool can act on. An agent can tell exactly what this tool does without opening the 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?

The description gives clear context for choosing among the three invocation modes (single notificationId, all-for-a-card cardId, or all:true), which is effectively usage guidance. It stops short of routing against alternatives such as list_notifications or stating any exclusions, so it is not a 5.

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