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

Annotations already establish readOnlyHint=true / openWorldHint=true, so the safety profile is covered. The description adds real context beyond that: the owner-key requirement, that private apps are decrypted with that key, and that single-component apps auto-select while multi-component apps return the available names. It does not mention whether the payment key is required for this call, which is the one behavioral 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 core action, and every clause carries information (scope, prerequisite, fallback behavior). No filler or restatement of the title.

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 6-parameter read-only tool with no output schema, the description covers the essentials an agent needs: what it returns (log lines), the auth requirement, and component resolution. It omits whether a payment key is consumed and any hint about output ordering or truncation, which leaves a small but real gap.

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 coverage is 67%, and the description genuinely adds meaning: "last N lines" clarifies the semantics/cap of the `lines` integer, "one of the nodes running it" maps to nodeIp, and the auto-pick/listing sentence explains `component` behavior not captured in the schema. It adds little on the two key parameters beyond what their schema descriptions already say.

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?

"Fetches the last N log lines of an app" gives a specific verb and resource, and "from one of the nodes running it" scopes it precisely. It is obviously distinct from flux_get_app / flux_get_app_stats, but it never explicitly contrasts itself with any sibling, so it stops short of a 5.

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 states a prerequisite ("Requires the owner key") and describes the conditional component-selection path, which implies how to invoke it correctly. However, there is no guidance on when to choose this over other inspection tools (flux_get_app, flux_get_app_stats) and no stated exclusions.

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