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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the mutation profile is covered by structured data. The description adds a policy gate against speculative calls, but says nothing about reversibility (messages_unhide exists) or the blast radius of markAllAsHidden beyond same grouping hash.

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 sentences, zero waste, and the core action is front-loaded ahead of the conditional caution. Every clause 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 destructive single-target mutation with no output schema and rich annotations, the description covers purpose, trigger condition, and a misuse warning. It could be more complete by noting the operation is reversible via messages_unhide and that markAllAsHidden affects sibling messages.

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%, so all three parameters, including the markAllAsHidden grouping-hash behavior, are already documented in the schema. The description adds no parameter-level meaning, which makes the baseline 3 the correct score.

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 and resource (hide a log message, by ID), which is immediately distinguishable from the sibling messages_unhide. It does not explicitly name the alternative, but the opposing verb makes the distinction self-evident.

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 a clear when-to-use condition tied to explicit user intent, plus an explicit when-not-to-use exclusion (never speculatively while investigating errors). It stops short of naming sibling alternatives such as messages_fix or messages_unhide for non-hiding cases.

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