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

The description far exceeds what annotations provide. It discloses validation behavior, integration storage, a complete errorCode taxonomy, the subtle subscription-tier gating gotcha that mimics missing_scopes, the promise that the token is never echoed back, and beta-status limitations. These behavioral traits are genuinely additive and help the agent reason about outcomes; there is no contradiction with the annotations.

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 long, but every sentence earns its place: purpose, validation behavior, prerequisites, success contract, error taxonomy, a subtle failure-mode explanation, security reassurance, and caveat. It is front-loaded with the core action before diving into edge cases, and there is no redundant filler.

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?

Despite having no output schema, the description covers the success return (success: true), all failure errorCodes, the trickiest failure nuance (tier gating masquerading as missing scopes), and beta-status expectations. For a connection tool with complex external failure modes, nothing critical an agent needs to invoke it correctly is missing.

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?

With only 50% schema coverage, the description compensates meaningfully: it documents the apiKey token format (pat-na1-…/pat-eu1-…) and ties parameter semantics to behavioral consequences (scope requirements, validation, error codes). The workspaceId parameter is already described in the schema, so the description need not repeat it.

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 states a specific verb (connect) plus resource (HubSpot portal) and the precise mechanism (Private App access token). It separates itself from sibling connection tools like campaignstack_connect_apollo and campaignstack_connect_instantly by binding the action to HubSpot and describing the validation workflow, not just restating the name.

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 description conveys clear usage context: it states the token format expected (pat-na1-… or pat-eu1-…), the mandatory scopes required, and what validation will occur (read ping + write-scope probe). It does not explicitly name alternatives or exclusion conditions, but the prerequisites effectively tell an agent whether it is in a position to call the tool successfully.

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