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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=true. The description adds useful context beyond that: it states the value is never read or changed, that expected_version 0 means no existing scope, and that an empty scope permits any public https host. It omits auth requirements and idempotency behavior despite the idempotency_key parameter.

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 compact sentences with no filler, and the core action plus versioning are front-loaded. The phrasing is dense and slightly awkward but each sentence conveys distinct rules (scope semantics, host format, non-mutation of value).

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 7-parameter mutation with no output schema, it covers purpose, host format, the empty-scope default, and that the secret value is untouched. It still leaves gaps on required fields (name, company, environment) and, given idempotentHint=false, on retry/permission behavior.

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 only 43%, but the description compensates for the two key parameters: hosts (format rules) and expected_version (0 for new scope). The remaining documented gaps (name pattern, company, environment enum) are left to the schema, so it adds value but does not fully cover the shortfall.

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 (set) and resource (the hosts scope for one saved credential) with the expected-version requirement. The closing 'Never reads or changes the value' distinguishes it from summer_credentials_set, though the phrasing is somewhat convoluted ('the hosts company actions may send one saved credential to').

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?

Provides clear format guidance ('exact https hosts, or https://*.example.com for any subdomain') and the empty-scope default behavior. However, it never explicitly says when to choose this over summer_credentials_set or summer_credentials_list; the sibling distinction is only implied by 'Never reads or changes the value.'

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