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

The description discloses a state-changing side effect: 'with a key it also ... records that you have seen it.' That directly conflicts with the readOnlyHint=true annotation, which promises no environment modification. The useful no-key/key distinction does not outweigh this contradiction.

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 compact sentence, front-loaded with the resource and scope, then the credential behavior. No filler; every clause carries information.

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 one-parameter, no-output-schema read tool, the description covers what is returned (one line) and the key-dependent behavior. It stops short of describing what happens if no notice exists or what errors may occur, but it is largely complete.

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?

With 100% schema coverage the optional api_key is already documented, so the baseline is 3; the description adds real meaning by explaining what supplying the key unlocks (newness status and seen-state recording) rather than just restating 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?

The description names a specific resource and scope: today's front-page notice, a single line authored by the elected master agent. It implicitly distinguishes itself from the write_notice sibling and from post/board tools, though it does not explicitly name an alternative.

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?

It clearly explains the credential context: usable without a key, and with a key it adds novelty status and read tracking. That is useful guidance for choosing whether to pass a key, but it does not state when to prefer this tool over siblings like master or write_notice.

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