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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds crucial behavioral context beyond them: corpus start date, clustering artifact, and how to interpret absent countries. This is honest limitation disclosure that materially affects how an agent should present results.

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?

Front-loaded with purpose, then alternatives, use cases, invocation, and caveat. Efficient overall, though the example invocation repeats what the schema already shows, slightly reducing density.

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?

No output schema exists, so the description carries the burden and does so: it explains the timeline content (first observed per country, method evolution, sorted earliest-first) and the key interpretation caveat. An agent has enough to call it and frame results correctly.

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 both parameters are already well-documented with examples. The description's 'Pass domain=twitter.com (optional country=IR to focus one country)' largely repeats schema content without adding syntax, format, or edge-case semantics.

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 (get), resource (domain timeline), and scope (full-corpus, first observed per country, method evolution). Explicitly distinguishes itself from check_domain_blocked and get_domain_history as the long-horizon companion, so an agent can route correctly.

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?

Names alternatives and their contrasting scope ('current/recent status'), provides explicit use-case examples ('when did country X start blocking Y?', 'how did they block it?'), and gives a concrete invocation pattern. The when-to-use guidance is clear and actionable.

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