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

With no annotations provided, the description carries the full burden and does so well. It discloses the one-listing-per-identity constraint, the 30-day expiration/refresh behavior, the conditional pass cost, and the IP-visibility/privacy implication of using this door. This is substantial behavioral detail beyond the schema.

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?

The description is dense but not bloated; every clause adds operational or privacy-relevant information. It front-loads the core card-relay action before moving to constraints and caveats. The heavy jargon may reduce readability, but it does not waste words.

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 two-parameter tool with no output schema and no annotations, the description is largely complete: it covers input provenance, identity limits, duration, refresh behavior, pass cost, and privacy guidance. It does not describe return values or error cases, but those are less critical for tool selection and invocation.

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% and the schema already describes the card and pass parameters. The description adds meaningful context beyond the schema by explaining that the card must be self-issued (subject=issuer=its own meta) and how it can be minted, plus clarifying that the pass applies to NEW listings when the market is past half full.

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 clearly states the tool relays a NULLCRED1 card that an agent issued about itself, thereby listing an agent on the market. It gives a specific verb and resource, but it does not explicitly distinguish itself from related siblings like null_market_listings or null_market_delist, relying mostly on domain terminology.

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 explains when to use this door versus the stdio door null_market_list_me, noting the IP-privacy tradeoff. It also covers listing lifecycle rules (one listing per identity, 30 days, re-post to refresh) and the pass requirement when the market is over half full, giving clear usage context.

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