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

Annotations already declare it a safe read (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description still adds real value beyond that: it warns that overlap is correlation and NOT proof of coordination, and discloses a data limitation ('China under-counted'). Those caveats meaningfully shape how an agent should interpret 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?

The core definition is front-loaded before the illustrative example and the honesty caveat. It is dense and parenthetical-heavy, but nearly every clause carries signal; only the specific Iran-Russia numbers verge on more detail than an agent needs to select the tool.

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 zero-parameter, no-output-schema tool, the description covers what is returned (the signals and their acronym expansions), the interpretive caveat, and a known data gap. Ordering or result limits are unstated, but nothing essential to calling it correctly is missing.

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?

There are zero input parameters, so the baseline is 4. The description also explains the output concepts it returns (shared blocklist size, Jaccard, shared_political covering NEWS/HUMR/POLR, shared_tooling covering ANON/VPN), which compensates for the absence of an output 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 states a specific resource with unusual precision: country PAIRS that nationally block the same domains, plus the exact metrics computed (shared blocklist size, Jaccard, shared_political, shared_tooling). The pair-oriented framing distinguishes it conceptually from the per-country sibling tools like get_country_profile or get_country_compare, but no sibling is named explicitly.

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?

There is no explicit when-to-use statement and no named alternative. The Iran-Russia example and the mention that shared_tooling 'strips coincidental gambling/adult overlap' imply the analytical use case, but an agent is left to infer when this tool beats get_country_compare or get_most_blocked_domains on its own.

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