ariel_get_timeline

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds that hours mode fetches all posts within a time window, and the schema adds 'max 500' and that cursor is ignored in hours mode. The description itself doesn't add much behavioral context beyond the schema, but annotations cover the main safety traits, so a 3 is appropriate.

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?

One clean sentence front-loads the main purpose and then gives the most important usage tip. There is no filler. It loses a point because it could also explicitly point to siblings or output considerations, but structurally it is efficient.

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 straightforward read-only timeline tool with fully documented parameters and annotations covering safety, the description is mostly complete. Gaps remain: no mention of what the response looks like (no output schema) and no explicit note that count is the default mode. These are minor, so a 3 is fair.

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 the schema fully documents all four parameters. The description reinforces hours mode behavior but adds no new semantics beyond what the schema already says. Baseline 3 is appropriate when the schema does the heavy lifting.

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: 'Get the authenticated user's home timeline.' It is clear that this returns a home timeline for the authenticated user, which is distinct from the sibling get_feed, get_author_feed, and get_posts. However, it doesn't explicitly name a sibling or distinguish itself in the way the highest-scoring examples do, so it falls just short of 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?

The description gives one usage hint: 'Use mode hours to fetch all posts within a time window.' This implies when to switch from the default count mode, but it doesn't say when to prefer this over siblings like get_feed or get_author_feed. It provides no exclusions or alternatives, so it is adequate but not explicit.

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