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

Annotations already cover readOnly, idempotent, openWorld and non-destructive, so the bar is lower. The description still adds real value: it enumerates what comes back (hosted endpoints or local setup links, provenance, evidence status, access model, limitations) and states the key behavioral constraint that the lookup never executes remote tools.

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?

Front-loaded with purpose, then return contents, then example questions, then the execution caveat. The three examples are slightly repetitive but each anchors a genuinely different query type, so the length is close to justified.

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 return-value burden and does so by listing the fields returned. For a one-parameter lookup tool this is nearly complete, missing only minor detail on result volume or ranking 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?

Single parameter with 100% schema description coverage, so the schema already carries the semantics. The description only implies the query is a provider/product/domain/protocol question, adding no syntax or format detail beyond the schema — the baseline 3 is appropriate.

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?

Specific verb ('look up') plus a precise resource ('official and community MCP/A2A products in the WagerX Agentic Gambling Index'). It is clearly distinguishable from the casino-oriented siblings and from the related get_agentic_stats.

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?

Three concrete example questions ('What is the official Crypto.com MCP?', the Binance/Bybit/WagerX case, 'Is ahel.io in the directory?') make the intended query shape unambiguous. It never names a when-not condition or points to get_agentic_stats as the alternative for aggregate statistics.

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