list_spam_blacklistLists sender entries that are always treated as spam in an account-wide blacklist; provide a domain you own to view the shared list.
Lists the account-wide blacklist: sender entries that are always treated as spam. The domain argument must be one you own, but the lists themselves are account-wide.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name on the MXroute account, e.g. example.com |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: the domain argument is an ownership/auth scope, while the blacklist entries returned are account-wide — a non-obvious scoping rule an agent would otherwise get wrong.
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?
Two sentences, zero waste, and the payload semantics are front-loaded before the scoping caveat. Every clause earns its place.
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 one-parameter read tool with 100% schema coverage and full annotations, the description covers the one trap (domain vs account-wide scope). It does not describe the shape of returned entries, but with no output schema that is a minor gap for a simple list operation.
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 schema already documents the domain pattern and gives an example. The description adds meaning beyond it by clarifying that the domain must be one you own and that it does not filter the returned entries — a real semantic distinction, not a restatement.
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 and resource ('Lists the account-wide blacklist') and immediately defines what that resource contains ('sender entries that are always treated as spam'). This is clearly distinguishable from the sibling tools list_spam_whitelist, add_spam_blacklist_entry, and remove_spam_blacklist_entry.
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 implies usage ('domain argument must be one you own') but never explicitly says when to reach for this tool versus the whitelist or the entry-management siblings. The scope caveat is helpful for calling correctly, but the routing guidance is only implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.