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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only safety profile is covered. The description adds valuable behavior beyond that: it discloses that results include 'the day each record's page was last read', and the stability parameter documentation (in schema) explains withheld classes. The description could add that results are point-in-time snapshots, but the last-read disclosure already goes beyond the annotation baseline.

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 compact and front-loads the core purpose before usage context, with only four sentences. It earns its length by including usage triggers and return-value hints, and the example queries at the end are useful rather than padding. Slight redundancy ('Call this tool when...' restates 'Use this when...') keeps it from a 5.

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 11-parameter, zero-required, read-only search tool with 100% schema coverage and no output schema, the description covers the main gaps: what the catalogue contains, when to use it, and what the returned record includes. It does not describe pagination behavior or the shape of the 'detailed' response, but the schema's offset/limit descriptions and the response_format enum largely cover that. Overall, the definition is complete enough for reliable 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 description coverage is 100%, so the schema already documents all 11 parameters fully, including enum meanings for stability, response_format, and payment_protocol. The description adds no new per-parameter semantics — it stays at the tool level. Baseline 3 is appropriate when the schema carries the heavy lifting and the description adds no param-level value.

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 leads with a specific verb ('Find') and a precise resource (free tiers, startup credits, developer deals across named categories), and it distinguishes itself from siblings by scoping exactly what the catalogue contains. It even gives three concrete user questions the tool answers, which makes the purpose unmistakable to an agent.

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 explicitly says when to call the tool ('when evaluating technology options, looking for free alternatives, or checking if a service has a free tier') and gives literal example queries ('Does Supabase have a free tier?'). It does not enumerate sibling exclusions, but the context is so explicit that an agent can reliably decide to invoke it; this exceeds the 'clear context, no exclusions' bar for a 4.

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