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

The description asserts "Read-only, changes nothing" while the annotations declare readOnlyHint=false, a direct conflict on the most safety-relevant trait an agent uses for gating. The description does add genuinely useful context (it inspects status, served content and sign-in walls, and falls back to a homepage probe), but the explicit contradiction with the readOnly annotation forces the lowest score.

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 core behaviour is front-loaded, but the sentence is a run-on with vague phrasing ("from any place live", "the place homepage link") that costs more parsing effort than it should. The trailing pricing metadata "(3 MESH/call, a tool · ops)" is useful for cost budgeting but is appended without structure.

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 single-parameter tool with no output schema, the description does a decent job covering the return semantics (status, what is served, sign-in wall vs. real site). It is incomplete on the two things that matter most here: the shape of the payload the agent must build, and a truthful account of the mutation/read-only profile that the annotation contradicts.

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 baseline applies even though the description says nothing about how to supply the link. Note that the schema's only parameter is a generic nested "input" object whose description cites agent-brain/agent-memory payloads, so it does not actually tell the agent that blog-link-check expects a URL — the description fails to compensate for that mismatch.

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?

"Checks a link ... live — status, what it actually serves, sign-in wall or real site" states a specific verb and resource and even enumerates the three outcomes the agent can expect, so the purpose is unmistakable. It never names a sibling (e.g. fetch, access-tight-check, deploy-live-check) as the alternative, so differentiation from neighbours is left implicit.

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 fallback behaviour ("if that link is missing, walks around to the place homepage link and checks that instead") implies the use case: verifying a blog link resolves to a real page. There is no explicit when-to-use vs. when-not, no statement of prerequisites, and no routing to siblings like fetch for plain retrieval or access-tight-check for gated content.

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