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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so safety is covered; the description adds genuinely new behavior: per-call cost of $0.1 USDC or credits, that payment credentials travel in MCP request headers (X-Payment / X-Payment-Tx / Authorization: Bearer fg_…) and must not be placed in parameters, and that unpaid access is truncated to 3 records. That header-placement instruction is exactly the kind of operational detail an agent cannot get from structured fields. It loses a point for not describing the shape of the returned statistics beyond field names.

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 lead sentence is well front-loaded and answers the practical question an agent's user would ask. But the body repeats the same content across English and Chinese blocks, and a further bilingual payment section duplicates the same $0.1 USDC / header facts, so roughly half the text is translation overhead rather than new information.

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 paid, parameterless, no-output-schema lookup, the definition covers the essentials an agent needs: cost, payment header mechanics, coverage window (2024-2025), breadth (11 schemes, new applications plus extension of stay), and the free-tier truncation caveat. The one unresolved gap is how a specific scheme is actually selected if no argument exists, which the description asserts but never reconciles.

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?

With zero parameters the baseline would be 4, but the description actively muddies this by saying '按计划代码查询该人才入境计划的完整统计' (query the full statistics for that scheme by scheme code) while the schema declares an empty properties object and the same description later states '入参：无' (args: none). An agent reading the prose will look for a scheme-code argument that does not exist, which is a real semantic defect even in a parameterless tool.

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 states a specific resource and scope: 2024-2025 application/approval/approval-rate statistics for Hong Kong talent admission schemes, with concrete examples (TTPS, QMAS) and an explicit 'full 11 schemes, two-year detail' extent. It is clearly a statistics-lookup tool, not a screening or quota tool. It stops short of 5 because the phrase '按计划代码查询' (query by scheme code) implies a selector the tool does not expose, leaving the actual unit of return slightly ambiguous.

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?

It does draw one useful boundary: the free tier returns only 3 records, and this tier is required for the full 11-scheme two-year breakdown, which tells the agent when the paid call is warranted. However, it never positions itself against the obvious siblings (scheme_list, scheme_digest, talent_quota) or states when an agent should prefer a list/lookup over this statistical payload. Usage is implied by the pricing/scope note rather than explicitly guided.

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