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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuinely new context: the call is free, and it discloses the shape of the payload (endpoint catalog, supported chains Base/Ethereum/XRPL, pricing, tokenized-equity aliases). It stops short of describing response structure or pagination, which is acceptable given the enumeration.

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?

A single front-loaded sentence: the cost qualifier 'FREE.' comes first, followed by the directory contents in a compact enumeration. No filler, no restatement of the title, and the most decision-relevant fact leads.

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 output schema, the description carries the burden of explaining return values, and it does so by listing the categories of information returned. A zero-parameter, read-only info tool is low complexity, so this is nearly complete; only the concrete response format is unspecified.

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 zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The description correctly implies a parameterless informational call rather than suggesting any inputs.

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 names the resource precisely — a service directory for the On-chain Forensics MCP server — and enumerates its contents (endpoint catalog, chains, pricing, aliases, examples). It implicitly distinguishes itself from the action-oriented siblings (token_profile, wallet_screen, settle_safe) by being pure metadata, but never states that contrast explicitly.

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 leading 'FREE.' signals the cost motivation for calling it and 'directory' implies a discovery use case, but there is no explicit when-to-use instruction such as 'call this first to find endpoints or check pricing before invoking paid tools.' Guidance is implied rather than stated.

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