osint_username_check

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

No annotations are supplied, so the description carries the full behavioral burden, and it discloses little beyond scope. It does not state that this performs live network lookups, whether results are cached, how false negatives (blocked/private profiles) are reported, or any rate/latency characteristics an agent would need before batching many calls.

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 sentence, front-loaded with the action and scope, with no wasted clauses. The 'OSINT Tool:' prefix is mildly redundant given the tool name already contains 'osint', but it usefully signals the category.

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?

An output schema exists, so return values need not be explained, and a single-parameter tool is inherently simple. However, with no annotations and no guidance on behavior or sibling selection, the definition is only minimally sufficient for an agent deciding when and how to call it.

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 is a single required parameter with 0% schema description coverage, so the schema contributes nothing. The description adds mild meaning by clarifying that the value is a 'handle/username' rather than a real name, but it does not specify accepted formats (with or without '@', URL form, case sensitivity).

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 gives a specific verb ('Check') and resource ('public presence and profile existence for a handle/username') plus scope ('across 25+ developer and creator platforms'). It is clearly distinct from data-extraction siblings like extract_pdf, though it does not explicitly differentiate itself from the closer OSINT siblings such as osint_deep_public_recon or osint_search.

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?

Usage is only implied: an agent can infer this is the tool for verifying whether a given handle exists on multiple platforms. There is no explicit statement of when to prefer it over osint_search or osint_deep_public_recon, and no exclusions or prerequisites are given.

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