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

Goes well beyond the annotations: annotations only say idempotentHint=true, non-destructive, closed-world, while the description explains that re-calling updates rather than fails, that no credential passes through the tool (credential_key is a secret NAME), that email has a platform fallback but Slack/WhatsApp do not deliver until configured, and that this sets the project default subject to tenant overrides.

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?

Information-dense and front-loaded with the core action, then layered by concern (provider choice, credentials, idempotency, fallbacks). Every sentence carries weight, though the multi-paragraph density is on the heavy side for a single tool.

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 an 8-parameter mutation tool with nested config and no output schema, the description covers the tricky operational details an agent needs: credential handling, provider selection pitfalls, idempotent re-runs, per-channel fallback behavior, and scope of the default. Nothing material is left unstated.

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 adds real meaning: provider behavior differences, that config.username is a LOGIN name defaulting to from_address with per-provider values, and the distinction that credential_key is a name not a live token. These enrich rather than restate the schema.

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 opening sentence names a specific verb (Configure) and resource (how a project delivers notifications on one channel) and immediately scopes it by excluding message text, naming the sibling set_notification_template that owns that concern. An agent can distinguish this from delete_notification_channel and set_notification_template without opening any schema.

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 explicit when-to-use guidance: use 'smtp' vs 'ses' with the reason ('ses' can only send as aaly.io), the Slack flow requiring set_secret first, and the note that a tenant can override via REST otherwise unreachable here. Alternatives and preconditions are named, not implied.

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