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

With no annotations, the description carries the behavioral burden and largely does so: it enumerates the returned fields (organizations, record counts, linked threat actors/malware/attack patterns, dates), which is essential since there is no output schema. It omits error behavior for a malformed or non-matching identifier, authentication needs, and pagination/size limits.

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 sentences, front-loaded with the action, then the return payload, then the two escalation paths. Nothing is redundant given the absence of an output schema, where the return-field list is genuinely load-bearing.

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 single-parameter read tool with no annotations and no output schema, the description covers action, identifier source, return contents, and alternatives — enough to call it correctly. Only failure modes and result-size expectations are left unstated.

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 100% and the schema already documents that identifier is "a UUID or the breach internal_name"; the description restates the same fact without adding format examples or validity rules. Baseline 3 applies because 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?

Names a specific verb and resource ("Fetch a single Mallory breach by identifier") and immediately constrains the domain to Mallory breaches with full detail. It is clearly distinguishable from listBreaches (listing) and queryApi (cross-entity), so an agent can route without opening schemas.

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?

Explicitly states the fallback path: "If you only have a name or search terms, call listBreaches first to find the exact identifier," and names queryApi for relationship pivots. Both the alternative and the condition selecting it are given.

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