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

readOnlyHint=true already declares the safety profile, so the description only needs to add context. It does: it discloses that the result includes both standard and custom objects with their fields, and names the underlying REST endpoint (GET /rest/metadata/objects). No pagination or response-shape details, but for an unpaginated metadata listing that is minor.

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 that front-loads purpose, then the discovery use case, then the endpoint reference. No filler; every clause carries information.

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?

With no params and no output schema, the description carries the burden of describing the return content, and it does so at a high level (objects plus fields, standard and custom). It stops short of describing the object/field shape an agent will parse, but that modest gap is acceptable for a discovery tool.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate. Baseline for a zero-parameter tool.

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 (List) and resource (metadata objects / schema fields), and explicitly scopes the result to standard + custom objects. It is trivially distinguishable from the sibling CRM entity tools (create/get/list company, person, etc.) which operate on records, not schema metadata.

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?

Gives a clear when-to-use: 'use this to discover custom objects/fields and valid field names.' That is actionable context an agent needs before writing filters or payloads. It does not name a specific alternative or state when not to use it, but the guidance is clear.

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