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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered by structured data. The description still adds real behavioral context beyond that: the tool has two modes (single-code lookup vs. full enumeration) and the input codes originate from reports, which tells the agent how to source its argument.

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?

Two short sentences, each carrying distinct information — capability plus fallback mode — with the primary purpose front-loaded. No filler or restatement of the title.

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 optional-parameter lookup tool with no output schema, this covers both invocation paths and the data source of the argument. What is missing is a hint about the shape of the answer (does it return only a definition, or also remediation steps and examples?), which matters given the description promises 'how to fix 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?

Schema coverage is 100%, so the baseline is 3, but the description goes past the schema by explaining the consequence of omitting the code (behavior changes to listing every code) rather than merely restating that 'code' is a string from a report. It does not cover case sensitivity or whether unknown codes error or return nothing, which would have justified a 5.

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+resource (explain a Test Bench issue code) and disambiguates further with three concrete code examples, which ties it to the domain of report issue codes rather than general terms. The second sentence adds a distinct second mode (list all codes when no code is given), so an agent knows exactly what it gets back in either case.

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 'without a code' clause implicitly documents the optional-parameter path, and the schema notes the code comes from a report, so the intended entry point is inferrable. However, no sibling is named as an alternative or exclusion — notably explain_term and explain_execution_request, which are adjacent 'explain' tools — leaving the agent to guess the boundary.

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