bhl.literature.by_subject
Browse the Biodiversity Heritage Library subject index to discover subject tags related to a natural-history discipline or concept (e.g. "ornithology", "botany", "entomology", "paleontology"). Returns a list of matching subject strings used to classify BHL holdings. Use the returned subjects as p...
This record as markdown: /tools/io-github-whiteknightonhorse-apibase/bhl.literature.by-subject.md
What bhl.literature.by_subject does on Apibase
AI agents call bhl.literature.by_subject to retrieve information from Apibase without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
subject | string | Yes | Subject keyword used in BHL classification (e.g. "ornithology", "botany", "entomology") |
Parameters from the server's own tool schema.
Why bhl.literature.by_subject is rated Low
Retrieves bibliographic metadata without modifying data or external effects.
From the tool's definition Browse subject index, discover subject tags, returns matching subjects
Attacks that exploit this kind of access
The rule that runs bhl.literature.by_subject safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Apibase, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For bhl.literature.by_subject, this is the rule to start with:
bhl.literature.by_subject is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Apibase, apply this rule, and every bhl.literature.by_subject call is checked against it from then on.
Questions about bhl.literature.by_subject
Browse the Biodiversity Heritage Library subject index to discover subject tags related to a natural-history discipline or concept (e.g. "ornithology", "botany", "entomology", "paleontology"). Returns a list of matching subject strings used to classify BHL holdings. Use the returned subjects as precise search terms in bhl.literature.search to retrieve publications filed under that subject heading. It is categorised as a Read tool in the Apibase MCP Server, which means it retrieves data without modifying state.
bhl.literature.by_subject accepts 1 parameter: subject. Required: subject. The full parameter table on this page comes from the server's own tool schema.
Register the Apibase MCP server in PolicyLayer and add a rule for bhl.literature.by_subject: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Apibase. Nothing to install.
bhl.literature.by_subject is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the bhl.literature.by_subject rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for bhl.literature.by_subject. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
bhl.literature.by_subject is provided by the Apibase MCP server (apibase-mcp-client). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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