List Instance Tables

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

Annotations already declare readOnlyHint=true and openWorldHint=true, setting a low bar. The description adds meaningful behavioral context by listing the returned fields and highlighting the filtering capabilities (prefix, scope, extendable-only), which go beyond the annotations. It does not mention side effects (none expected) or pagination, but the schema covers limit/offset. Overall, it enriches the behavioral picture.

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 description is three sentences, each earning its place: the first states purpose and output, the second differentiates from a sibling, the third gives usage direction. It is tightly written with no fluff, and the key information is front-loaded in the first sentence.

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?

Combined with the schema (which fully documents all 7 parameters with descriptions) and annotations (readOnly, openWorld), the description provides complete context for an agent to make an informed call. It covers the tool's purpose, return value fields, use cases, and relationship to a sibling tool. No critical information is missing for a read-only listing function.

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 the baseline is 3. The description does not add significant semantic meaning to parameters; it merely rephrases 'name_prefix', 'scope', and 'extendable_only' as 'prefix filters, scope filters, and extendable-only mode' in the usage guidance. This is helpful for context but does not add detail beyond the schema's own parameter descriptions.

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 clearly states the tool's purpose: 'List tables on a ServiceNow instance with optional filtering.' It includes the specific resource (tables on an instance) and the return fields (name, label, parent class, scope, extendable). It also distinguishes itself from the sibling 'lookup_table' by contrasting filtering approaches, making the purpose unambiguous.

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?

Explicit guidance is provided: 'Unlike lookup_table (which searches by name or label keyword), this tool supports browsing with prefix filters, scope filters, and extendable-only mode. Use this to discover tables in a specific scope or browse tables by naming convention.' This tells the agent when to choose this tool over an alternative and gives concrete use cases.

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